Frank Ocean Sued -- He Didn't Want Chipotle Logo in Chipotle Ad

Frank Ocean wanted to have his burrito and eat it too -- metaphorically speaking -- because Chipotle Mexican Grill just sued the singer for backing out of an ad ... for what seems like the most ridiculous reason.

According to the suit, filed today in L.A. County ... Chipotle signed Frank to a $425,000 deal to sing a remake of "Pure Imagination" for a new animated ad.

But Chipotle claims Frank never recorded the track because when they showed him the final cut ... Frank was pissed the company's logo appeared at the end of the spot.

To reiterate ... he was mad Chipotle's logo was in a Chipotle advertisement.

The restaurant says it got an email from Frank's people claiming Frank thought he was promised final say over the recording and all promotional materials -- and believed the company was in breach when it refused to remove its logo.

Chipotle is suing to get back the $212,500 advance it paid Ocean.

By the way, Fiona Apple ended up doing the spot instead of Frank.