Brain injury charity Headway says the injury sustained by France defender Benjamin Pavard and the way it was dealt with was "sickening to watch".
Pavard was injured in the Euro 2020 Group F clash on Tuesday night at the Allianz Arena when he collided with Germany's Robin Gosens.
The defender hit the ground without his arms protecting him from the fall and later admitted he was "a little knocked out for 10, 15 seconds".
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Despite this, the player was allowed to continue after receiving on-pitch medical attention for less than three minutes - a decision labelled by Headway as "disturbing".
Peter McCabe, chief executive of Headway, said: "This is another example of football authorities failing to protect the short and long-term health of a player.
"It was plain for all to see that Pavard was unable to protect himself from the fall. Pavard's later statement that he lost consciousness confirms the seriousness of the incident.
"We have continuously been told that football's concussion protocols are fit for purpose and that temporary concussion substitutes are not necessary.
"But here we have yet another example where it is simply not credible to suggest that a concussion could not be 'suspected' or a possible consequence of the impact. However, after a brief on-pitch assessment the player was allowed to continue.
"Furthermore, it appeared that the referee was attempting to speed up the medical team and usher them and the player off the pitch, rather than allowing them the time they needed to assess the seriousness of the injury.
"Why is it so hard for football to accept it has got this wrong and follow the example set by other sports by introducing temporary concussion substitutes?
"The way this incident was handled was sickening to watch. UEFA has to come out and immediately explain how it was allowed to happen and what action it will now take to ensure something similar does not occur in the future."
UEFA told Sky Sports News the French Football Federation is responsible for following the concussion protocols all teams signed up to ahead of Euro 2020.
European football's governing body has contacted the FFF to explain why Pavard remained on the pitch after the collision during Tuesday night's game.