Henry has been appointed as Monaco's head coach following the departure of Ligue 1 title-winning boss Leonardo Jardim, with the Arsenal great making the move to Stade Louis II following links to a number of other clubs.
Pires sees this as the right move and he is enthused by the presence of a pair of ex-Gunners on the touchline in France this season.
"I think this is the right time for Thierry Henry. For a long time, he has wanted to be a manager," Pires told Sky Sports News. "Of course, I think he was waiting for a good opportunity.
"Monaco is a great opportunity, because he started with Monaco when he was a young player and now it's like he's at home. He knows the club, he knows the staff. For him, it was important to take this opportunity.
"In France, all the people are very happy because it is important they can see a new face on the bench like Thierry Henry or like Patrick Vieira, the manager of Nice in Ligue 1.
"Sometimes you need some fresh faces. That's why I'm very happy for Patrick and Thierry. I think both of them can be a success in Ligue 1."
Henry was unveiled as the team's manager on Wednesday, where he revealed that he views Arsene Wenger and Pep Guardiola as two major influences on his coaching career.
Monaco have just six points from nine matches, and Henry will be given time to adjust the team, but the former Arsenal star believes he can right the ship sooner rather than later.
Former New York City coach Vieira took charge of Nice ahead of the current season, with his side 12th in the table after nine matches. They face Henry's Monaco in December.