Alexandre Lacazette could face disciplinary action from Arsenal after the club said they will "seriously" look into an alleged incident involving the striker and a balloon.
Footage, first reported in The Sun newspaper on Saturday, appears to show the 28-year-old with a balloon in his mouth. He is alleged to have sent text messages saying "at home, chilling and doing balloons."
Lacazette has been in trouble with the club over nitrous oxide balloons in the past. In August 2018, the striker was pictured inhaling balloons alongside teammates Mesut Ozil, Matteo Guendouzi and Pierre-Emerick Aubameyang, with the players involved later reminded of their responsibilities by the club.
A club spokesperson told the Guardian: "This is a private matter which we are taking seriously. It will be handled internally."
Nitrous oxide is not illegal in Britain but experts say recreational use can be dangerous.
Arsenal have resumed individual training at their training base in Colney, north London amid the shutdown. Meanwhile, Premier League clubs are yet to begin group training, although the league could resume behind closed doors in June after the British government set out a road map to emerge from coronavirus lockdown measures earlier this week.
Clubs hopeful of a June 8 restart, and to finish by the end of July and fit in with UEFA's European competition plans.