First feature to really kick butt is that Woodcutter’s Camps hold more Citizens : what an advantage in early game when you ALLWAYS need wood and you can't afford to build a new Woodcutter’s Camps because you need food on everything !! The Incr. Timber Commerce Limit also makes this advantage ever better in early game, plus the free upgrades for wood later saves you some ressources.
The Supply Wagons heal units. This is a HUGE advantage in battles. It allows your army to last longer and also to heal without garrison them. But also it allows you to COUNTER STRIKE your opponent ! After he attacked you, and while his army is anihilated, you still have some army and you can strike back one of its nearest city. With the supply wagon ready, you can cause serious damage to his econ.
Then comes the "free Supply Wagon with each new Siege Factory" feature. This is great also because those damn supply wagon cost a lot in early game. So recieving this free wagon is great for attack of course, but also for defense since it will heal your troops.
The free General is great as well for defense with entrench and for attack with decoy etc ...
So my point is : the Frenches recieve a great bonus for early econ, and also recieve a great DEFENSIVE AND/OR AGRESSIE BONUS with the supply wagon + general features. A French player can really be UNPREDICTABLE as he can be aggressive and/or defensive. This features leave him lots of possibilities and strategies through the game.
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Plus you see Frenches are overpowered in this game cause 3 of their wonders are available (Versailles, Eiffel Tower, SoL ...)