At the risk of sounding like a broken record......why are there 2 languages being used???
Because the French are conducting operations in accordance with the requirements paragraph 5.2.1.2 of Annex 10 to the Chicago Convention and communicating in english to those aircraft that request it:
5.2.1.2 Language to be used
5.2.1.2.1 The air-ground radiotelephony communications
shall be conducted in the language normally used by the
station on the ground or in the English language.
5.2.1.2.2 The English language shall be available, on
request from any aircraft station, at all stations on the ground
serving designated airports and routes used by international air
services.
5.2.1.2.3 The languages available at a given station on the
ground shall form part of the Aeronautical Information
Publications and other published aeronautical information
concerning such facilities.