Depending on your nationality and your status in France you might have to request a temporay resident card - titre de séjour:

Researcher from an EU country

Researcher or doctoral candidate and their family from a country of the European Union, Switzerland or the European Economic Area (EEE)

Researcher from a third-party country

Steps to take if the researcher is from a third-party country

 

Algerian nationals

Steps to take if you are Algerian

Doctoral candidates

Steps to take if you are a pursuing a PhD thesis in France