Fontainebleau is the poster child for courses in desperate need of chainsaw intervention. It should be the most outstanding golf course in France. I haven't been down there for a few years now, but one of their members told me last week that they had done a great deal of clearing. However, from the photos posted here, it hasn't changed a bit in the past four years.
I have heard that tree removal is an issue due to the bureaucracy involved with the national forestry office, which apparently has jurisdiction there, but I don't know that for sure.
St. Germain (Colt) is the most overlooked of the Parisian courses, and with Morfontaine and Fontainebleau, forms an outstanding threesome.
I find Chantilly (Simpson) to be less interesting. I though the holes were redundant, I remember lots and lots of cross bunkers, and the terrain flat, but I only played it once years ago, and it may have changed, or I may not have appreciated its subtlety.
St. Cloud, originally another Colt, is the closest to Paris. It's overgrown with trees, too, but at least some of them are magnificent hard wood specimens that add to the atmosphere. It is the only course that affordsl a view of the Eiffel tower on certain holes. They have begun cutting out some of the rubbish trees, and the maintenance is steadily improving. There are still recognizable pieces of Colt in there. It's worth a look, if you have a day to kill and can't get on to the big three Morfontaine, Fontenbleau., or St. Germain.