The Gunners’ captain’s request was denied and he retaliated by refusing to travel on the club’s pre-season tour of the USA.
Arsenal issued a statement condemning Koscielny’s actions and could yet strip him of the captaincy.
The central defender has reportedly been offered a three-year contract by Bordeaux, amid interest from Lyon and Rennes also.
According to The Mirror, Koscielny felt Arsenal’s offer of a one-year extension to his current deal effectively amounted to a pay cut.
While BBC Sport reporter David Ornstein says the Frenchman’s decision has left club chiefs stunned.
“Arsenal had been in talks with Koscielny over his future since late last season,” said the transfer guru.
“And, at that point, the club felt things were moving in a positive direction.
“However, the 33-year-old returned from his summer break and asked to be released from his contract a year before it expires, which Arsenal refused.
Arsenal/Koscielny talks late last season looked +ve. Back from break, asked for release, refused. Relayed tour decision Wed, confirmed @ Colney today. Flight 1230 without him. Not stripped of captaincy yet, must train or breach contract. #AFC have no offers, he does if free agent
— David Ornstein (@bbcsport_david) July 11, 2019
“Negotiations have been taking place over the past few weeks, without resolution.
“On Wednesday, Koscielny communicated his intention not to join the squad on their pre-season tour to the USA – and on arrival at the Gunners’ London Colney training ground this morning he confirmed this decision.
“The flight was due to depart at 12:30 BST without the Frenchman who, while facing disciplinary measures, will be expected to continue training.
“If he refuses to do so will be in breach of contract. He has not been stripped of the captaincy as things stand.
“Koscielny’s behaviour has stunned Arsenal officials, who were already looking to use the transfer market to strengthen in central defence but had no intention of parting with their skipper unless a suitable offer arrived.
“As yet they have received no offers, but it is understood Koscielny has options lined up that would see him return to France if he was a free agent.”
Arsenal paid Lorient £10m for Koscielny back in 2010 and he has since won two FA Cups with the Emirates outfit.
The 33-year-old has played 353 games for the Gunners but he now seems unlikely to wear the shirt again.