The French club parted company with Deakin yesterday because of differences between him and the players.
Former Great Britain coach David Waite, who had been working as a consultant to the Perpignan-based outfit, will take temporary charge until a permanent successor can be found.
General manager Christophe Levy told l’Equipe: “He has been removed from his functions as coach for incompatibility with the players.”
Deakin was appointed by the club, then known as Union Treiziste Catalan, in 2003 to oversee their preparations for entry to Super League. Under his guidance they won the French cup and league double last year.
Deakin had been working as assistant coach at Huddersfield after previous spells with London Broncos, Keighley and Sheffield.
Australian Waite, who stepped down as Britain coach after the 2003 Ashes series, will be assisted by Paul Donkin and Sebastien Munoz.