The Welshman prevailed in a blood and thunder maiden bout on foreign soil and will now turn his attention to several potentially mouth-watering domestic clashes which surely lie ahead.
Newbridge-boxer Rees signalled his intent early with a stunning right hand to the nose in an opening round which clearly rocked his opponent.
Two further forceful right hooks left their mark on Mezaache in the second, but it was a nasty clash of heads in the third that left the home boxer with real cause for concern.
Blood was pouring down the challenger's head following the clash and Rees heaped more pain on his opponent with a number of telling shots which left him clinging on.
A miraculous clean-up operation saw Mezaache come out much more refreshed in an even fourth and Rees was forced to absorb a couple of classy combinations from the Parisian in the next.
But the Welshman never appeared in any serious danger and turned on the style in the seventh with a flurry of shots to head and body.
A slick right hand over the top gave him a knockdown and he swifly finished the job with a flurry of unanswered punches which forced the referee to intervene.
Speaking after the bout, Rees, who has now won 36 professional fights, told Sky Sports: "I felt great, it's boiling in here. I started jabbing and followed it up with some nice shots on the outside. He didn't really hurt me tonight [Saturday], I won every round and stopped him in good fashion.
"I keep telling everyone I can punch at lightweight and I think I showed that tonight [Saturday]. I always seem to dig in when it gets tough."