(Mishnah): If a spark flew out from a man's hammer and it damaged, he is liable.

If Reuven's camel, laden with flax, was walking in a Reshus ha'Rabim, and the flax entered Shimon's store, caught fire from Shimon's lamp, and burned the building, Reuven is liable;

If Shimon left his lamp outside, he is liable.

R. Yehudah says, if it was Ner Chanukah, he is exempt.

(Gemara - Beraisa - R. Yehudah): If it was Ner Chanukah, he is exempt, for he had permission;

Chachamim say, in either case he is liable.

People like these who make Sukos in the openings of their stores during Sukos, because it is permitted, if one came and was damaged through them, he is liable. (CHASAM SOFER, from the RASHBA - Chachamim said so to R. Yehudah, and that the same applies to Ner Chanukah. R. Yehudah distinguishes, for Sukah need not be in Reshus ha'Rabim, but one must put Ner Chanukah at the opening of his Chatzer.)