It's been awhile I have seen this film but from what I can remember when I saw it as a kid: I liked it. A small boy is left (with or without babysitter? I don't remember) alone at home (huge mansion) while his parents attend a dinner party on christmas eve. The boy named Thomas thinks he is safe until a burglar dressed in Santa Claus decides to drop in and do some christmas shopping. So now begins this cat & mouse game as Thomas is determined to defend himself and his home. Think more in the lines of "Rambo kid Home Alone without that Culkin brat". Good film from what I can remember and I'm still trying to find a copy of this french film. Perhaps I liked it because I was about the same age as the hero of the film who had these self-made weapons, cool gadgets and was fighting against this psycho santa claus dressed burglar.
For those who wonder what 36.15 is: it's not the code for "Pere Noel" (Santa Claus) but in France it's like a "teletext" or "internet/bbs" function back in the 80's/early 90's. Basically you type in 36.15 and then a "name/word" (e.g. 36.15 CINEMA) and you can find info. Sort of like an electronic yellow pages server.