Unfortunately, with a few exceptions, within SkyTeam (and ditto within *A and OW), elite status on one airline has no impact on upgrading. This is the case between AF and CO.

There have been rumors that ST would roll out a "SkyTeam Upgrade" program similar to the "Star Alliance Upgrades" that was rolled out last year and is progressively adding more and more of the *A airlines (UA, ANA, Asiana, Austrian Airlines Group, LOT Polish Airlines, Lufthansa, Swiss International Air Lines, TAP Portugal and Thai Air, so far). I only hope the rumors are true.

You will have all of the "elite plus" (not Platinum) benefits:
• Lounge Access (except on purely domestic U.S. itineraries)
• Guaranteed Reservations on Sold-Out Flights
• Priority Baggage Handling
• Priority Check-In
• Preferred Seating
• Priority Boarding
• Priority Reservation Waitlist
• Priority Airport Standby
• Elite Qualification Miles