BOYCE F. MARTIN, Jr., J., delivered the opinión of the court, in which MOORE, J., joined. KENNEDY, J. (pp. 464-69), delivered a separate dissenting opinion.
*460BOYCE F. MARTIN, Jr., Circuit Judge.The City of Fairfield appeals the district court’s grant of a preliminary injunction prohibiting the City on First Amendment grounds from enforcing a municipal ordinance against Lynn Tucker, Jr. and other members of his union in their use of a rat balloon as part of demonstrations in a public right-of-way. For the following reasons, we AFFIRM the judgment of the district court.
I.
Lynn Tucker, Jr. is the General Vice President of the Eastern Regional Office of the International Association of Machinists and Aerospace Workers. Tucker and several of his fellow union members picketed Fairfield Ford, a car dealership in Fair-field, Ohio, on three primary occasions in 2003 (February 26, July 1, and July 31) for alleged unfair labor practices. The protests all took place in the public right-of-way between Fairfield Ford and Dixie Highway, with each involving somewhere between twenty-five and forty protesters and generally lasting between one and two hours.
During these protests, Tucker and his colleagues held signs and displayed an inflatable rat balloon measuring approximately twelve feet high and eight feet in diameter. The rat has long been used as a symbol of efforts to protest unfair labor practices. The rat balloon in the instant case can be inflated or deflated within five to ten minutes, and is temporarily secured to the ground with stakes to ensure that it does not tip over.
The conflict in this case arises out of the application of the City’s ordinance prohibiting structures in the public right-of-way to the Union’s use of the rat balloon. Section 905.03(c) of the municipal code provides that “[n]o person, firm or corporation shall construct or place or cause the construction or placement of any ... structure or improvement ... on any street, alley, public right-of-way, easement or public grounds without the written permission of the Public Works Director.” As originally enacted, the ordinance defined “structure” as “anything constructed, the use .of which requires permanent location on the ground or attachment to something having permanent location on the ground, and also includes anything constructed which is not enclosed within another structure and is placed in a stationary location.” The City later amended the definition of “structure” on September 13, 2003, with the express intent of covering the use of the balloon in this case.1 The amendment defined a “structure” in relevant part as “any object, whether permanent or temporary, including, but not limited to, nonpublic signs, that is constructed, erected or placed in a stationary location on the ground or is attached to or placed upon an object constructed, erected, or placed in a stationary location on the ground.”
The first demonstration using the rat balloon in front of Fairfield Ford occurred on February 26, 2003. While the Union notified the police that they would be using the balloon during its protest, and Fair-field Ford called the police to complain about the demonstration, no arrests were made or citations issued over the use of the balloon. The second demonstration occurred on July 1 at the same location. The Union again notified the police of its *461plans to protest. This time, Janette Mat-tala, a zoning inspector for the City, came to the scene and warned the protestors that they would have to remove the balloon or be subject to arrest. Police officers, who later arrived on the scene, also allegedly threatened the protestors with arrest. Consequently, the protesters deflated the balloon. The third demonstration occurred on July 31. During this protest, Tucker and his fellow Union members again displayed the rat balloon. At this demonstration, however, Tucker was given a citation for violating the city ordinance prohibiting structures in the public right-of-way. Notably, there is no evidence in the record indicating that the protests, including the use of the balloon, created any obstruction or safety hazard.
On August 27, 2003, Tucker and his Union filed a Complaint, Motion for a Temporary Restraining Order, and Motion for a Preliminary Injunction in the District Court for the Southern District of Ohio, claiming that the application of the City’s ordinance to the use of the balloon violated the First Amendment. On August 29, the court issued a temporary restraining order, which expired on September 15. The court then held a hearing on the preliminary injunction on September 15, and, on October 27, granted Tucker’s motion for a preliminary injunction, finding, among other things, that Tucker had demonstrated a likelihood of success on his claim that the City’s efforts to prevent the Union from using the balloon during its demonstrations violated the First Amendment. The City timely appealed that decision to this Court on November 7, 2003.
II.
The only question presented in this case is whether the district court erred in granting a preliminary, injunction prohibiting the City of Fairfield from restraining Tucker and his union from using the rat balloon during their labor protests on the public right-of-way in front of Fairfield Ford. This Court reviews a district court’s grant of a preliminary injunction for an abuse of discretion. Keweenaw Bay Indian Cmty. v. Michigan, 11 F.3d 1341, 1348 (6th Cir.1993). A district court abuses its discretion when it relies on clearly erroneous findings of fact, improperly applies the law-, or uses an erroneous legal standard. Deja Vu of Nashville, Inc. v. Metro. Gov’t of Nashville & Davidson County, 274 F.3d 377, 400 (6th Cir.2001).
When determining whether to grant a preliminary injunction, a district court must consider: “(1) the plaintiffs likelihood of success on the merits; (2) whether the plaintiff may suffer irreparable harm absent the injunction; (3) whether granting the injunction will cause substantial harm to others; and (4) the impact of an injunction upon the public interest.” Id:
The district court considered these four factors and granted Tucker’s motion for a preliminary injunction. The court found that Tucker had “a very high likelihood of success on the merits” of his claim based on “a First Amendment right to use portable, non-obstructive props to disseminate information in a public right-of-way on a temporary, or ■ limited basis.” The court held that the ordinance, as applied to the use of the rat balloon, unconstitutionally infringed- on this right. The court also found that the remaining factors weighed in favor of granting the injunction. According to the court, the suppression of Tucker’s protected speech constituted irreparable harm to the Union and the use of the balloon was not shown to harm others. Moreover, the court found that the public interest weighed in favor- of protecting First Amendment rights. Consequently, the court, having found.all *462factors in Tucker’s favor, issued the preliminary injunction.. For the following reasons, we hold that the district court did not abuse its discretion in granting the preliminary injunction.
A.
The First Amendment broadly provides that “Congress shall make no law ... abridging the freedom of speech.” U.S. Const, amend. I. In our view, there is no question that the use of a rat balloon to publicize a labor protest is constitutionally protected expression within' the parameters of the First Amendment, especially given the symbol’s close nexus tq the Union’s message. See, e.g., Int’l Union of Operating Eng’rs, Local 150, AFL-CIO v. Village of Orland Park, 139 F.Supp.2d 950, 958 (N.D.Ill.2001) (“We easily conclude that a large inflatable rat is protected, symbolic speech.”).
The central claim asserted by the City on appeal is that there is no constitutional right to maintain a structure in a public right-of-way. As this Court has pointed out before, however, “whether there is such a right depends upon the property and the government’s regulation of that property.” Chabad of S. Ohio & Congregation Lubavitch v. City of Cincinnati, 363 F.3d 427, 434 (6th Cir.2004).
Courts have generally refused to protect on First Amendment grounds the placement of objects on public property where the objects are permanent or otherwise not easily moved. For instance, in Graff v. City of Chicago, 9 F.3d 1309, 1314 (7th Cir.1993) '(en banc), the court considered whether a news vendor had a First Amendment right to maintain a newsstand on public property. The court rejected the claim, holding that “no person has a constitutional right to erect or maintain a structure on the public way.” Id. As the Graff court pointed out, however, newsstands are “large, permanent-type structures” that “are not easily moved.” Id. at 1315. In distinguishing newsstands from news-racks, which have received more favorable First Amendment protection, see City of Lakewood v. Plain Dealer Publ’g Co., 486 U.S. 750, 772, 108 S.Ct. 2138, 100 L.Ed.2d 771 (1988) (holding unconstitutional an ordinance giving the mayor discretion to grant or deny applications for permits to place newsracks on public property), the court expressly noted that “newsstands compared to newsracks are much larger, more permanent structures that occupy a significant portion of limited sidewalk space.” Graff, 9 F.3d at 1315.
A similar result was reached in Lubavitch Chabad House, Inc. v. City of Chicago, 917 F.2d 341, 346-48 (7th Cir.1990), wher'e the court rejected a constitutional challenge to the City’s refusal to allow a menorah to be erected in a public area of O’Hare Airport during Christmas time. The court noted the difficulty that would be involved in allowing all individuals to erect “free-standing” structures on public grounds, and expressly found no constitutional right to do so. Id. at 347.
Unlike the more permanent structures analyzed in Graff and Lubavitch, the balloon in the instant case is temporary and easily movable. The Union only uses the balloon during its protests, which last just one to two hours, and the balloon has not been shown to cause any danger that could justify a restriction of the balloon’s use. As the district court pointed out, at least one federal court has adopted a similar approach in analyzing whether the use of “structures” on public property is constitutionally protected speech. See One World One Family Now, Inc. v. Nevada, 860 F.Supp. 1457, 1462-63 (D.Nev.1994) (holding that group’s portable tables were afforded First Amendment protection because of their limited use in facilitating the *463sale of expressive t-shirts, while chairs, umbrellas, and boxes were not protected because they were not sufficiently related to the expressive message and constituted “permanent-type” structures). Thus, given the existing case law on this subject, we hold that the district court did not abuse its discretion in finding that the use of the portable rat balloon on the public right-of-way is deserving of First Amendment protection.
Having held that the district court did not abuse its discretion in finding that the use of the balloon on the public right-of-way is constitutionally protected expression, the issue next becomes whether the City may nevertheless prohibit Tucker and his Union from using the balloon during its protests. “The Supreme Court has adopted a forum analysis ‘as a means of determining when the government’s interest in limiting the use of its property to its intended purpose outweighs the interest of those wishing to use the property for other purposes.’ ” United Food & Commercial Workers Local 1099 v. City of Sidney, 364 F.3d 738, 746 (6th Cir.2004) (quoting Cornelius v. NAACP Legal Def. & Educ. Fund, Inc., 473 U.S. 788, 800, 105 S.Ct. 3439, 87 L.Ed.2d 567 (1985)). Three types of fora are generally recognized: the traditional public forum, the designated public forum, and the nonpublic forum. Id. A traditional public forum is a place “which by long tradition or by government fiat ha[s] been devoted to assembly and debate.” Perry Educ. Ass’n v. Perry Local Educators’ Ass’n, 460 U.S. 37, 46, 103 S.Ct. 948, 74 L.Ed.2d 794 (1983). In our view, the district court did not abuse its discretion in finding that the forum in this case — a public right-of-way— is a traditional public forum, given the fact that both streets and sidewalks are generally considered traditional public fora. See, e.g., Frisby v. Schultz, 487 U.S. 474, 480, 108 S.Ct. 2495, 101 L.Ed.2d 420 (1988) (noting its decisions holding that streets and sidewalks are traditional public fora); Rappa v. New Castle County, 18 F.3d 1043, 1070-71 (3d Cir.1994) (holding that public rights-of-way are properly considered traditional public fora).
“In traditional public fora, ‘the rights of the state to limit expressive activity are sharply circumscribed’: the government may enforce ... content-neutral time, place, and manner regulations only if they are,‘narrowly tailored to serve a significant government interest, and leave open ample alternative channels of communication.’ ” Kincaid v. Gibson, 236 F.3d 342, 348 (6th Cir.2001) (quoting Perry, 460 U.S. at 45, 103 S.Ct. 948). The district court found that the ordinance here was not a content-based restriction on speech, and that finding apparently is pot challenged before us. Thus, for the purposes of this appeal, we assume that this finding was correct.2 Therefore, the ordinance is constitutional as applied if it is narrowly tailored to serve a significant government interest, leaving open other alternative channels of communication.
In this context, “the requirement of narrow tailoring is satisfied so long as the ... regulation promotes a substantial government interest that would be achieved less effectively absent the regulation,” and does not “burden substantially more speech than is necessary to further the government’s legitimate interests.” Ward v. Rock Against Racism, 491 U.S. 781, 799, 109 S.Ct. 2746, 105 L.Ed.2d 661 (1989) (quotation marks and citations omit*464ted). Importantly, however, the regulation “need not be the least-restrictive or least-intrusive means” of serving the government’s interests. Id. We agree with the district court’s finding that the ordinance does not appear to be narrowly tailored as applied to the Union’s use of the balloon. In our view, the asserted government interests of keeping the public right-of-way clear and preserving the aesthetics of the community, while generally considered substantial, are simply not achieved any less effectively absent the application of the ordinance in this ease. There is no objective evidence in the record before us suggesting that the temporary placement of the balloon in the public right-of-way has any adverse effects, such as obstruction of pedestrian or automobile traffic. By applying the ordinance to prohibit the temporary use of the balloon in this case, it therefore appears that the City has applied its ordinance in a manner that is “substantially broader than necessary” to achieve its interests. See, e.g., Cleveland Area Bd. of Realtors v. City of Euclid, 88 F.3d 382, 388 (6th Cir.1996) (holding unconstitutional ordinances regulating the placement of signs in residential neighborhoods because they burdened “substantially more speech than necessary,” despite city’s “significant government interest” in aesthetics). Thus, the district court did not abuse its discretion in finding that the Union has demonstrated a likelihood of success on the merits.
B.
The district court also found that the remaining factors weighed in favor of granting the injunction. The City does not appear to challenge these holdings on appeal. We note, however, that the district court’s decision on each issue was proper. First, the application of the City’s ordinance prohibiting the Union’s use of the balloon, and the consequential adverse effect on Union organizational efforts, are sufficient to constitute irreparable harm. See, e.g., Elrod v. Burns, 427 U.S. 347, 373, 96 S.Ct. 2673, 49 L.Ed.2d 547 (1976) (“The loss of First Amendment freedoms, for even minimal periods of time, unquestionably constitutes irreparable injury.”). Second, the use of the balloon in the right-of-way has not' been shown to create any obstruction or other safety hazard, suggesting that granting the injunction will not cause substantial harm to others. Finally, the public interest factor in this case clearly weighs in favor of protecting the First Amendment, rights of the Union’s members. See, e.g., Chabad, 363 F.3d at 436 (noting that “the public interest is served by preventing the violation of constitutional rights”). Accordingly, the district court did not abuse its discretion in holding that the relevant factors support the issuance of the preliminary injunction in this case.
III.
For the stated reasons, we hold that the district court did not abuse its discretion in granting Tucker’s motion for a preliminary injunction, and we therefore AFFIRM the decision of the district court.
. The Fairfield City Council’s express intent to cover "objects such as the inflatable rat involved in the Tucker litigation” is illustrated by the amendment’s preamble, which clearly states that the Council's purpose in enacting the amendment was "to amend its codified ordinances to further clarify that objects such as the inflatable rat are prohibited from the public right-of-way whether placed there on a temporary or permanent basis.”
. We note that it appears that the amended ordinance, with its express purpose of prohibiting the use of the rat balloon, may not be content-neutral. We reserve judgment on this question, however, until the district court fully considers the issue on the merits.