While contracts for the purchase of lands involving the obligation of the vendors to furnish paving and other improvement *Page 542 to the lands that are included in a municipality, may not prevent the exercise of the municipal power to levy special assessments on the lands for pavements or other proper local public improvements, and the exercise of the governmental power may not relieve the vendors of their obligations to purchasers of lands to provide paving and other improvements as a part of the consideration for the purchase price for the lands, yet whereas in this case it appears that the municipal action for special assessments to provide the paving and other improvements was influenced by and participated in by agents or employes of the private corporation vendor who was obligated to provide the pavement, etc., such municipal action is thereby rendered invalid and ineffectual, even if the required formalities and orderly procedure had been observed in the municipal action taken in this case to issue bonds for paving and the levy of special assessments to pay the bonds. The municipal power to levy special assessments cannot be utilized to relieve, supersede or postpone the obligations of persons or corporations to provide local public improvement that might otherwise be provided for by special assessments where the municipality acts within the requirements of law uninfluenced by unlawful considerations.