Arsenal legend Ian Wright claims Laurent Koscielny "should be ashamed" after his move to Bordeaux was announced with the Frenchman throwing off a Gunners shirt.
Ex-Arsenal captain Koscielny belatedly sealed a return to Ligue 1 on Tuesday, having refused to travel on the Premier League club's pre-season tour.
The nature of the transfer had already upset many Arsenal fans, and a social media video prompted further outrage on the day of his switch.
A clip, shared by Bordeaux, showed Koscielny taking off his Arsenal shirt to reveal his new club's top underneath.
Wright was among those unimpressed, posting on Twitter: "This hurts. The level of disrespect. You should be ashamed for the way you've left the club after nine years!
"Got what you wanted and still trying to have a dig. Hope it's worth it in the long run."
Meanwhile, Koscielny sought to explain his exit to Arsenal fans on his Instagram page.
"As you know, I engaged with Bordeaux," he wrote. "After nine years spent at Arsenal, I took the decision to leave.
"I have spent wonderful years with this club, nine years during which I learned, evolved, grew up. This experience made me the player I am today.
"My decision to leave has been discussed for months with my club, my team-mates, my coach, and it has been a well-thought decision.
"I see this departure like a new turning point in my life as a player but also in in my life as a man and a family man.
"However, I hope you understand, and in any case, I cannot be thankful enough for these years past at Arsenal. I am aware of everything that the club and you supporters have brought to me.
"But it is time for me to go home, so today my will is to join Bordeaux. This is a new challenge that I count on taking with determination."
Arsenal are said to be looking to sign a new centre-back in the final two days of the transfer window, having struggled defensively last season even before Koscielny's departure.