I know this answer is probably not relevant anymore to you (and probably you won't see this), but perhaps there are other people stuck in this level, so I might as well help them with this answer.
In Chateau Villette, after you solve al the riddles, you get attacked by Silas (he's the crazy monk, for those who haven't read the book or seen the movie).
Before you can grab the globe, Silas enters and grabs Robert. You (as Sophie) take the poke from the fireplace and try to hit him with it, but he takes the poke from you and throws it away. Then he attacks you. You should now follow the 'combo' that appears on the screen to defend yourself. Do it fast enough and make sure it's the right combination. If you can defend yourself, Robert will get the poke and hit Silas and you can go to the next room. Each time Silas punches you (when you didn't get the defence combination right) you loose half of your health, so two punches means you have to start over. In the second room, you can find some bandages (don't know if this is the right term, 'cause I play the game in Dutch) to restore your health, if you need it.
Actually, the difficulty of this level depends a lot on your computer mouse. If it doesn't work for you, and especially when you have trouble with left and right clicking together, it may help to use another mouse. I started this game on my brother's computer and I just couldn't click together (sorry, don't know how to say this in English). I must have started over hundreds of times, it just didn't work. So I installed the game on my own computer and started over again. So last week, I discovered that this level was actually very easy. Had to start again just once. I have less trouble with the fighting too, now. Bit sad that whether or not you can play the game properly should depend on what mouse you use...