If it is a private house, it is the responsibility of the real estate administrative department of the local people's government at or above the county level, or you can directly find the Urban Construction Bureau/Urban Management Bureau.
The most direct way is to report to the local people's government.
The general treatment method includes several parts:
Ordered to restore and dismantle illegal buildings within a time limit. And give a warning.
Impose a fine of 1000 yuan but not more than 5,000 yuan on the owners and property users, and impose a fine of not less than 5,000 yuan but not more than 50,000 yuan on the decoration enterprises;
If it is not removed within the time limit, the construction administrative department of the people's government at or above the county level may apply to the people's court for compulsory execution.
If it is property management, it can also be fined according to article 2, and the money will be included in the community management fund.
Neighborhood harmony is very important. In order to handle this matter smoothly, both sides need to look at the problem objectively and understand each other.