The classic story, except that the French, of course, can't have alligators in their sewers like everybody else:

The Guardian
March 9, 1984
Page 8

Sewer croc

FIREMEN yesterday snared a young crocodile in Paris sewers. Officials said that the crocodile, taken to an aquarium, was thought to have been illegally smuggled into France as a baby and then flushed away after it became too large to handle. --AP