Boulahrouz - who still has one year to run on his Chelsea contract - was sent out on loan to Sevilla last season, but Marseille boss Gerets has seen enough in the 26-year-old to consider making an offer.
"I have handed a list of the reinforcements that I want to the board and he (Boulahrouz) is on it," Gerets told De Telegraaf.
"It is now up to them to contact Chelsea. If that will happen I do not know. It could do.
"I don't know how much Boulahrouz would cost. That is not my area. But I would really like to have him."
Meanwhile, Boulahrouz insists he is unaware of any approach from Marseille.
"I have agreed with my agent that I will only be informed when I can sign," said Boulahrouz.