Breaking into the Ligue 1 side last season, the 18-year-old only made 19 appearances before heading to north London.
And the defender has revealed how he came to a decision.
In the clip, Saliba is doing his first interview with the Gunners.
And the interviewer asks if the teenager spoke to any of Unai Emery’s stars before moving.
The new boy says: “Yeah, I spoke to Matteo [Guendouzi].”
Moving from Lorient last summer, the midfielder made 48 appearances for the Gunners last season.
And he made three appearances for France at the Under-21 European Championships.
But the 20-year-old had a big part to play in Saliba’s transfer – and it was all by chance.
“I bumped into him at a fun fair in Paris,” the defender added.
“That’s where I told him that Arsenal wanted to sign me.
“He gently advised me to come here and explained what it was like.”
This footage was shared on the club’s official Instagram channel this morning, where it has been viewed more than 100,000 times.
And the Gunners faithful hailed their young midfielder for his part in the transfer.
“I bumped into him at a fun fair in Paris”
“Matteo slowly becoming a fan favourite,” one supporter said.
Another commented: “You love to see it.”
While a third simply said: “Agent Matteo.”
It comes as Saliba’s potential position in the Gunners XI has ben revealed.