César

César is one of two hostile French wine/leather makers who force Bart to be their slave and try to kill an endangered blue snake for leather. His nephew is Ugolín.

History
The two are the owners and only employees (aside from Maurice the Donkey) of the Chateau Maison wine orchard. They use the foreign exchange student program to get Bart from the U.S. and have him work for them as their slave, to replace their donkey. They are very mean men and they give Bart very little food, force him to sleep on the ground, and make him taste the filled wine.

They had not waited long enough for their wine to ferment, so had decided to add Anti-Freeze to it for flavor. They got Bart to taste-test it (making sure he hadn't gone blind after drinking it), then sent Bart out to get some more Anti-Freeze. This turned out to be their undoing: Once Bart realized he had subliminally learnt fluent French, he told a passing police officer everything, and César and Ugolín were arrested. It is assumed they went to a French prison.

Later they are seen watching TV in an apartment, implying that they were either released from jail or placed on parole.

He eventually becomes a hostile leather maker who tries to kill the blue snake that Homer was supposed to give them to pay for a trip to France, he tries to forcefully get it back, but ultimately fails.

Non-canon
They are seen as two of the surrendering French men in The Simpsons Game level, "Medal of Homer".

Trivia

 * César and Ugolín are the names of two of the main characters from Marcel Pagnol's novel collection "L'Eau des collines" which consists of "Jean de Florette" and "Manon des sources".