''Camille Claudel,'' showing at the Charles, is the story of Claudel's very long descent into madness. The film, two and one-half hours long, should run no more than 90 minutes, but director Bruno Nuyten apparently wanted us to share in all this agony, which we do.
Claudel, who lived from 1864 to 1943, was collaborator then mistress to Auguste Rodin, the French sculptor. He already had a family, but that didn't deter Claudel who, when Rodin refused to leave his wife and children, began her ride to hell.
Isabelle Adjani plays Claudel. She won an Academy Award nomination for her work in the film and deserved it. She is rather remarkable as she travels the road to madness, but then she played a similar role in ''The Story of Adele H.'' Gerard Depardieu is Rodin.
''Camille Claudel'' will remain at the Charles through Wednesday. It's a big, beautiful bore.