French and Ottomans (and JD) are the only civilizations with access to a cannon ship in the Castle Age. The French Galleass will tear through any ship the Ottoman can make.

Historically this matchup is a bit scary in the early parts of the feudal age for the Ottomans and then it gets progressively easier as they set up military schools and begin pumping Sipahi and spears to counter the French's knights and archers. It becomes very difficult for the French from a unit control perspective because Mehter alongside the Sipahi and spearman makes such a fearful composition. On a map with less room for archers to kite and easier choke points, it can be even scarier.

Janissaries deal well with knights, but need numbers to be effective.

The Twin Minaret Medrese is going to allow the Ottoman player to out-sustain French aggression.

Going to Castle Age for the Ottomans is usually a vulnerability point against civilizations like the French.