The little fort with the blue-and-yellow flag belongs to the Burgundians? I already wondered what the Russians were doing in France .

The Burgundians are a hidden faction, a bit like the Swiss. They only appear in late and only because of a 'faction resurrection' event. But even this is rare: I understand Burgundy first has to become neutral before the resurrection takes place. Historically, Burgundy was given by the French king (Jean II I think it was) to one of his sons. However, the new dukes of Burgundy did not feel much loyalty to the French crown, which had been severly weakened by the hundred years war. They tended to make deals with the English and the Holy Roman Empire at the cost of the French. However, since the game cannot represent this situation they made Burgundy a bit like the Horde, except that it doesn't appear on a set time.