1. A controversy that causes public debate. The town's polluted drinking water became a national cause célêbre when it was discovered that the local leaders had allowed it to happen.
2. A legal case that is famous or celebrated. The trial became a cause célêbre for those who felt the defendant was victimized by the legal system.
a famous event or legal case which people discuss a lot because it is so interesting or shocking The relationship between Edward Prince of Wales and Wallis Simpson became an international cause célêbre in the 1930s.