Benjamin Pavard revealed he was knocked out for "10 to 15 seconds" before returning to the field in France's 1-0 win over Germany at Euro 2020.
Pavard sustained a head injury following a collision with Germany's Robin Gosens as world champions France opened their Group F campaign with victory on Tuesday.
France defender Pavard was left on the floor before receiving treatment for several minutes in Munich, where he was eventually allowed to continue.
"I took a hell of a shock," Pavard told beIN Sports post-match.
"I was a little knocked out for 10 to 15 seconds. After that, it was better."
A "concussion charter" was signed by all 24 teams at Euro 2020 – a commitment to taking a series of measures to improve the care of players and includes neurological baseline testing and access to in-match television replays for team doctors.