Stephan will be the eighth manager Chair has played under at QPR.
The Frenchman has an impressive CV, having led his hometown club Rennes to a French Cup triumph in 2019 – their first trophy for 48 years.
Rangers have not sustained a promotion challenge since being relegated from the top flight 10 years ago.
They are not among the favourites to go up this time around, but will be hoping Stephan can help them beat the odds.
“He’s been great. He has different ideas and I’m listening a lot to him,” Chair said.
“He has this sort of charisma. He has an aura about him, which maybe I haven’t experienced with other managers – other managers have had other qualities.
“He definitely has something special about him, which is very good for us as players.
“I wish I’d known him longer. I spoke to a couple of players that have played under him and they’ve been positive about him, and so far so good with us.”
QPR begin their Championship campaign with a home match against Preston on Saturday.
