Deposit for furnished apartment

I will rent a furnished apartment. The landlord asked me the amount equivalent to two months rent for security deposit, is that legal ?

What is a solidary guarantee ?

The solidary guarantee, a solution when a tenant is in financial difficulty.

Device Scellier - Carrez

Device Scellier-Carrez, or how to pay significantly less tax and build assets for less than 200 Euros/month ?