Light/Med French get autoloaders at tier 5, Heavies - at tier 8. They are all very dangerous, you will be sorry if you ignore a tiny French light even if you are in a tier 10 tank.
In order to fight them successfuly, you need to deny them their main advantage - shooting speed. Get out, shoot, hide back. Any French tank, except tier 10 heavy, can potentially kill its same tier opponent with one cartridge, don’t ever get caught in the open by them. If you have teammates also shootnig at him, always try to get their tracks. Generally aim at their turret - their ammo, radioman and commander get killed very easily (and killing either means longer reload for the autoloader, the long one, not the one between the shots) and the turret is much easier to penetrate on AMX120 and AMX50b (other French tanks are easily penetrated anywhere).
Counting their shots and watching their behaviour also helps - the long reload is quite significant but only on high tier tanks. On AMX12t and AMX13-75 it’s only about 12-15 seconds, you can’t do much while it reloads. Top gun on AMX13-90 takes about 35 seconds, Lorraine - 50 sec, BatChat - 30 sec, AMX50-100 - 45 sec, AMX50-120 - 35 sec, AMX50b - 25 sec. Careful with AMX13-90, while its top gun has a long 35 seconds reload, the stock one takes only 12 seconds. All French tanks have 6 shots in a cartridge, except for the top gun on AMX50-120 and, of course, AMX50b.
T29’s ears have been fixed, penetrating them does not deal any damage now. R2D2 on KV-5 though is still a weak spot.
As for the skill, I always recommend getting stealth, it always helps to be a bit less visible and potentially get a first shot at an enemy. Also think ahead, while Tiger may catch on fire a little bit too often (not THAT bad though and nothing a fire extinguisher can’t help with), none of the higher tanks in that tree have this issue (well, except for E-100 but it’s a different story and one needs to know where to shoot).
On the other hand though, supposedly, next patch will bring new crew skills and skill respec, so it doesn’t matter much what you get now.
Also, don’t get new crew skills when you are almost done with the tank. Drive a little with the pluses, the crew will still accumulate the exp and will use it automatically when you train them for a new tank. I switched from AMX50-100 to AMX50-120, paid silver for training to get 90% but all that accumulated exp resulted in them becoming 100% right from the start. Sweet.