Hi ethandron, just seen your post! The meal is on the 24th at night (called reveillon) and consists of (basically) oysters, smoked salmon, foie gras, goose with chestnuts, cheese then chocolate log. Presents are opened at midnight. Next day, around lunchtime it's off again for more or less the same thing!
I must say, it's very easy to organise a French Xmas for families who have split up as the kids go to one parent for the reveillon and the other parent the next day... It's also convenient as a couple to go to one set of parents on the 24th and the other set the 25th! Everybody's happy.