Diddy wants Dawn Richard‘s civil suit against him thrown out … calling the allegations she’s made against him totally false — on the same day she took the witness stand against him in his criminal trial.

The rap mogul’s legal team filed the documents Friday … pointing out a series of reasons why Dawn’s lawsuit shouldn’t go any further — statute of limitations, improper group pleads, and on and on.

It’s mostly lawyer speak … though Diddy’s attorneys do say early on in the docs that she’s essentially trying to ride the wave of negative press around Diddy to a payout — writing Dawn “seeks to transform narratives of alleged injuries against others into a headline-grabbing sex trafficking conspiracy as to her.”

What’s more interesting than the actual words in the document is the timing of the dismissal … ’cause it was filed on the very same day Dawn took the stand in Diddy’s federal sex trafficking trial.

As we told you … Dawn told the court she saw Diddy violently attack Cassie — specifically referring to an alleged 2009 incident where she says she watched Diddy attempt to hit Cassie with a frying pan.

She also alleged that Diddy told her and a bandmate to keep quiet on what she says went down.

Dawn’s also supposed to take the stand again Monday as the trial heads into Week 2 … though Diddy’s ex Cassie has officially finished her testimony in the case — and is now focusing on giving birth to her third child with Alex Fine.

Richard filed a lawsuit against Diddy back in September … claiming he groped, terrorized, and belittled her while working on the show “Making the Band.”

Diddy’s lawyers called BS at the time … telling us, “In an attempt to rewrite history, Dawn Richard has now manufactured a series of false claims all in the hopes of trying to get a pay day” — adding that if things were so bad on “Making the Band” then Dawn wouldn’t have agreed to sign another contract with Diddy later on.