Zsa Zsa Gabor: Citizen's Arrest FAIL at Home ... 'You Freeze and Shut Up!'

Zsa Zsa Gabor's husband tried to take a locksmith into custody -- after fighting with him over a $700 bill -- but police had to be called to back him up.

Prince Frederic von Anhalt tells TMZ he'd hired the locksmith to fix a door in Zsa Zsa's bedroom, but was floored when the guy said it cost $700! The Prince refused to pay and the two got into a heated argument.

Check out the video ... Prince von A. says he doesn't stand for "za dirty language" in front of Zsa Zsa, and that's why he tried to make a citizen's arrest. Didn't go so well, and when real cops arrived ... the locksmith had left the property.