Oksana's $15 Million Lawyer Goes After Her

2/19/2011 5:45 PM PST

Oksana Grigorieva's $15 Million Lawyer Goes After Her

TMZ has learned ...the lawyer who negotiated the $15 million settlement with Oksana Grigorieva -- the settlement she signed and then disavowed -- is going after her for his fee.

Eric George has initiated legal action against Mel Gibson's ex, claiming he did his job in securing a settlement, and the fact that she later disavowed it does not let her off the hook in paying his fee.

According to arbitration documents -- obtained by TMZ -- George's firm is entitled to 10% of the compensation he won for Oksana.  The total sum of the settlement was $15 million, but we're told George's fee did not include a percentage of the portion that was earmarked for child support.

Oksana has refused to pay George and filed legal docs trying to dismiss his claim, but we've learned that motion was denied. 

The D.A. is now considering whether to file extortion charges against Oksana, with Mel's camp claiming she used the explosive audio tapes as leverage to make the $15 million deal -- threatening to release them if she didn't get paid.