cause célèbre 

A cause or issue, generally political, that arouses public opinion. From French, meaning “celebrated cause.” (as taken from the New Dictionary of Cultural Literacy).

The question of the draft was a cause célèbre in the 1960s.

cause célèbre by LFJ February 10, 2006

cause de celebre 

a cause or charity so over-hyped by media and/or celebrities it makes the general public feel brow beaten, turning them against the cause

The Truth campaign ads for anti-smoking, the cause de celebre, are so preachy they make me want to start smoking.

cause de celebre by paperBRAINS January 30, 2010