Dieng was a regular for Marseille over the course of last season, but the club were willing to sell him in the summer, with Leeds coming close to capturing him.
The striker has made just one appearance in Ligue 1 and scored only a solitary goal though, as he is out of favour and tipped to be on the move this month.
Marseille’s fellow Ligue 1 side Lorient have reached an agreement for the services of the striker and he looks set to head to them.
However, Leeds and Everton have attempted to hijack the deal for the 22-year old, with the latter trying more forcefully, according to French journalist Mohamed Toubache-Ter.
The Senegalese star has his heart set on Lorient and does not look to be Premier League bound.
Dieng and his agent made it clear that they were convinced by Lorient’s project and reassured by the playing-time they are expecting at the French club.
Everton have been victims of a late swoop for one of their targets, Arnaut Danjuma, who is now snubbing them to go to Tottenham Hotspur.
It is unclear exactly when Everton and Leeds looked to tempt Dieng this month.