It depends on your lease agreement that you have made with the real estate company.

if it is mentioned a notice period of one month for termination before the expiry of the lease period then there is a one month rent normally that is charged.

However in some lease agreements it will be stated that if the contract is terminated before the lease period is not completed then the tenant needs to pay the rest of the months rent(number of months left).

You need to verify your contract if any of the above clauses are mentioned and if you have signed then you need to pay.

One month or Two months notice period is actually to let them know if you need to renew the lease nearing to the expiry of the lease period.

Hope the above answers your question.