The club were known to be trailing centre-half Souare, who can also play left-back and in midfield, this winter and have reportedly agreed a £4million deal for the Lille players.
Souare, 24, has made 18 appearances for Lille this season and has recently returned from Africa Cup of Nations duty with Senegal.
Parish tweeted: "Delighted that @papesouare has just this minute signed for #cpfc. A warm welcome from all of us."
Souare joins Jordan Mutch as new faces in the Eagles dressing room as newly-appointed manager Alan Pardew seeks to keep the club in the Premier League.
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy