As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#1907, JFK-CDG. (AIRCRAFT PERFORMED AN AIR TURN BACK). 'AIR PACK 1 REGUL FAULT MESSAGE INFLIGHT AT CRUISE. BLEED PAGE SHOWS XX FOR LEFT PACK TEMP; FOUND P1 COM TEMP SENSOR (12HH) TO BE AT FAULT. REMOVED AND REPLACED P1 COMP TEMP SENSOR (12HH) REF AMM 21-61-11. OPS CHECK OK.'