France is very interesting.
I had my best game in the last two months starting as the Count of Tours in 1066. He has some really good skills and he has traits like Ambitious, Envious, Deceitful and Greedy. Plus, he's an Anjou, which is a cool dynasty.
Perfect char to first murder your mediocre older brother and become Duke of Anjou. Then start to plot your way to the french throne. I married the younger capetian sister of the king, then civil war erupted shortly after. It actually lasted a long while, with house Capet and house of Burgundy clashing with each other for three decades for the throne, with the occasional minor claimant arising here and there, plus of course other kinds of rebellions. I would act as kingmaker all this time, being allied to both houses (my son was married to a De Bourgogne), and deciding which one to help depending on the circumstances. In the meanwhile, I preyed on my neighbours (including the temporarily powerless capetian house) and expanded greatly. When I was ready to strike, both house de Bourgogne and house Capet were exhausted, after three decades of continuing warfare and strife. House Capet's head was imprisoned by the De Bourgogne, and the young De Bourgogne king was a kid under a regency. My regency. It was time to strike and push my son's claim to the throne. After a brief war (most of France was backing me) the throne was won, and the rule of House D'Anjou began. My original character was 70 years old back then, and had the short pleasure of seeing his son on the throne of France. Then he died. Naturally, I had to fight even more wars vs the Capetians and the De Bourgogne. Each one of those fuckers pushed his claim in succession. So yeah, peace didn't really follow. Then I overwrote the save out of a mistake =_=
At any rate, France in 1066 is very interesting. It will devolve in a long civil war in which many claimants will try to win the throne, and if you play your cards right you can sit on the throne in one generation. Once you've won the throne and consolidated your position, you can think about expanding. I'd say the natural objectives of France are:
A) First and foremost, unifying the territories of France, and keeping Aquitaine and France united.
B) If Spain is overrun by muslims, stopping the muslims.
C) Crusading. A lot of crusaders in history were french.
D) Curbing the power of the Holy Roman Emperor. If you see that they are fighting an independence war, then it's time to strike.
E) Obtaining power within the Curia, and perhaps bring the papacy to Avignon by making the bishop of Avignon an Antipope and then pushing his claim.
F) Last but not least, expanding. The D'Anjou for instance were a very expansionist house. The natural and historical place for french expansion is Italy. It's in a strategic position, it's very wealthy, a good base for crusades, and in a perfect position to influence papal politics. House Anjou historically held the kingdom of Naples: try to win that throne.