I've never had a problem in France with French controllers not using reasonable English - but maybe that's because I haven't flown to the places Whirly went to.
The particular problem is not normally controlled fields. These are normally bilingual and the only gripe for non-french-speakers is that the mixture of languages dramatically affects situational awareness.
The real problem is when you get airfields such as Granville that have no controller (or FISO) and are operated on the basis of UNICOM-style air-to-air calls. This so-called "Auto-information" needs to be in French and like any UNICOM system, listening to and understanding the other aircraft that are using the field is at least important as broadcasting your intentions.
2D