How did he get on with French after that? I maintain that not all students are going to be excel at all subjects, and grinds can put extra pressure on the situation, if the student is genuinely weak in a particular area. For example, how disappointing would it be for a student (not referring to your son) to get a D a subject with the teacher only, then have 4 months of grinds and still get a D?
My son got a C in hons french. His first two years in secondary were very good in that subject. He then got this new/other teacher and he went downhill as did the rest of the class. Apparently the class average was D. I fully agree that children at this stage in their development do not need extra pressure but you have to agree that some teenagers are just plain lazy and need a little shove.
Parents need to realise their own childrens abilities and encourage rather than force. I believe a childs social development and self esteem is equally if not more important and very much needed in todays world.