The 23-year-old made 29 appearances for Ligue 1 side Rennes last term but will now ply his trade in the Premier League after penning a four-year deal at the Cardiff City Stadium
The 23-year-old has penned a four-year deal with the Premier League outfit, becoming their seventh signing of a busy transfer window following promotion from the Championship.
And following his side's 0-0 draw with Everton, Bluebirds boss Malky Mackay expressed delight over capturing the Frenchman's signature.
"He [Theophile-Catherine] is someone we have tracked and watched for a period of time. He brings defensive strength and solidity to us," he told reporters.
"We have to make sure we have cover everywhere and that we have players who are pushing each other. Kevin brings that from a top division in French football."
Theophile-Catherine - who is a product of Rennes' youth academy - made 29 appearances for the Ligue 1 side last term.
He has also been capped by France at Under-20 and Under-21 level.