Is it legal to set up large signboards at public elevators?

1 illegal, the owner next door infringes on your neighboring rights, which refers to the rights enjoyed by the owner or user of real estate when dealing with neighboring relations. Specifically, between the owners or users of adjacent real estate, any party has the right to ask other neighboring parties to provide convenience or accept certain restrictions in order to reasonably exercise its ownership or use right. Neighboring right is essentially the limitation and extension of ownership. In other words, the top of the elevator entrance also belongs to you. If you have a property management office there, you can complain there. If it can't be solved, you can bring a lawsuit to the court.

2. According to the Property Law, because I don't know your specific situation, the relevant provisions of the Property Law are as follows:

Eighty-fourth adjacent owners of real estate should correctly handle the adjacent relationship in accordance with the principles of favorable production, convenient life, solidarity and mutual assistance, fairness and reasonableness.

Eighty-fifth laws and regulations on the handling of adjacent relations, in accordance with its provisions; Where there are no provisions in laws and regulations, local customs can be followed.

Article 86 The owner of a property shall provide necessary convenience for the neighboring owners to use water and drain water.

The utilization of natural running water should be reasonably distributed among the adjacent owners of real estate. The discharge of natural running water should respect the natural flow direction.

Eighty-seventh real estate owners should provide necessary convenience for neighboring rights holders to use their land for traffic and other reasons.

Article 88 Where the owner of a real estate needs to use adjacent land or buildings for building or repairing houses and laying wires, cables, water pipes, heating and gas pipelines, the owner of the land or building shall provide necessary convenience.

Article 89 The construction of buildings shall not violate the relevant national engineering construction standards, and shall not interfere with the ventilation, lighting and sunshine of adjacent buildings.

Article 90 Owners shall not abandon solid wastes or discharge harmful substances such as air pollutants, water pollutants, noise, light and electromagnetic wave radiation in violation of state regulations.

Article 91 A real estate owner may not dig a hole to borrow soil, build a building, lay pipelines or install equipment, which will endanger the safety of adjacent real estate.

Ninety-second property owners use adjacent properties for reasons such as water use, drainage, traffic, laying pipelines, etc. We should try our best to avoid causing damage to neighboring real estate owners; If damage is caused, compensation shall be made.

I insist on building a harmonious socialist society, so I hope you can discuss it with the owners first, and try your best not to waste judicial resources.