Marseille, who drew 1-1 with Rangers in a friendly on Saturday, are on a mission to bolster their squad after two seasons of domestic failure and have significant financial clout after a takeover by American businessman Frank McCourt last October.
Manager Rudi Garcia wants to strengthen his strike-force and has already added Valere Germain, Florian Thauvin and Clinton N’Jie to his squad for this season, but is understood to want a pacey, strong frontman to spearhead his attack and France Under-21 striker Dembele fits the bill.
Dembele has earned plenty of positive reports in his homeland over the past year after scoring 32 goals for club and country last season and a plethora of big clubs have been linked with him, including Chelsea, Arsenal, Everton and AC Milan.
However, Marseille hope to steal a march on other suitors and bring the former PSG youngster back to France with a £20m offer, report Sky Sports.
Celtic manager Brendan Rodgers signed Dembele from Fulham for just £500,000 last summer and although he reiterated earlier in the transfer window that he would not entertain bids for him until after the Champions League qualifiers, the Scottish champions’ resolve is sure to be tested by multi-million pound bids in the coming weeks.