I caught the ending of this movie several times on cable in the 80s. It was in color, and the version I saw was in English, but it might have been overdubbed because it had a very continental European vibe to it, possibly French. Made in the 70s or 80s.
The villain was some kind of religious cult leader, I think. The good guys needed to steal some sort of magical artifact, maybe a stone, that was under very tight security. One of them asked how they were going to do it. The main character replied something like, “Simple. We’ll fly.” The heist involved the use of climbing ropes and carabiners to cross the room along the ceiling to avoid setting off the alarms.
When the main character finally gets the magical stone, its power turns him into some kind of half-monster, like half of his face becomes deformed. But it also gives him the power to beat the bad guy. That’s about all I remember.