Everton had already settled on a deal with the French club for the Nigerian stopper and now the 22-year-old and his advisors have agreed on a deal with Goodison Park officials.
Yobo originally moved to Merseyside on a £1 million one-year loan deal from l'OM but Everton will now pay a further £3.5 million for his permanent signature.
Toffees boss David Moyes has been delighted with the imposing displays from Yobo and was keen to get the deal done and dusted as soon as possible.
The contract will not be signed until the winter transfer window in January, when the African will pen a contract for a further four years following the completion of the current campaign.
Yobo's outstanding form in defence was one of the reason's behind Everton's solid displays that saw them go five Premiership games without conceding on their recent good run.
