If the contract has been actually performed, it is valid. If all the contract copies are not signed by the other party, then the contract is not established. There is no question of effectiveness. If the other party has signed it, but the party holding the contract has not signed it. It will take effect after the retaining party signs it up. Legal objectivity:

Article 54 of the Law of the People's Republic of China on Urban Real Estate Management, the lessor and the lessee shall sign a written lease contract, stipulating the lease term, lease purpose, lease price, repair responsibility and other rights and obligations of both parties, and register with the real estate management department.