I own an apartment that is currently rented out. The lease is about to expire: can I take back the property to use it as a pied-à-terre?

No. The property must necessarily become your principal residence (French Supreme Court, 3rd Civil Chamber, 31 January 2001, No. 99-11.956). This means you must occupy the property effectively and permanently, and it must be the center of your family interests.

The tenant may hold you liable and seek the annulment of the notice (French Supreme Court, 3rd Civil Chamber, 31 October 2006, No. 05-19.293), or even claim damages (French Supreme Court, 3rd Civil Chamber, 19 April 2000, No. 98-21.124).