Full-back Medard suffered the injury in Sunday's 23-17 victory over Scotland, during which he scored a crucial try, and will undergo an MRI scan to discover how long he is likely to be sidelined for.
Announcing the decision to restore Poitrenaud, head coach Phillipe Saint-Andre told L'Equipe: "He is an obvious choice. There are not many (full-backs) in our squad.
"There were one or two options but we have chosen Clement, who will be joining us this afternoon."
Alexis Palisson was one potential option for Saint-Andre, but was overlooked due to a lack of game time in the position with his club.
"(Palisson) does not play full-back with Toulon. We do not need a winger who can play full-back but a real number 15," the coach said.
The match in Paris had originally been scheduled for February 4 but was postponed just before kick-off due to a frozen pitch.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
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Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
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The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.