The ex-Blues, Arsenal, and Barcelona star believes they need to reduce the size of their squad.
Chelsea are looking to sell players, especially those who are homegrown, with the likes of Trevoh Chalobah on the docket.
As part of bet365’s Euro 2024 coverage, Petit said: “Every transfer window, we have the same questions about Chelsea. I saw they were looking at Jonathan David from Lille, but don’t they have enough players already?
“I think they have enough players. If they want to bring more players, they need to sell first. I mean, before thinking about bringing new players, try to sell some of them.
“They also need to keep hold of Conor Gallagher.
“Every time I open a newspaper or I go on the internet, I see so many players linked with Chelsea. They can only play with 11 players on the pitch. So what's the point of bringing again so many more players having only just brought in a new manager?
“So it's gonna take weeks, weeks, months to set up everything, to understand the tactical organization, the management, everything.
“If they are happy to change 40% of the dressing room every six months then good luck to them. I don't get it, to be honest with you.”