First of all, when Messi left the bench to get prepared for his substitution, both the home and away fans started chanting Leo's name. The Argentine responded with a shy wave.
The same happened during the match, as the crowd cheered every time the 34-year-old got on the ball.
After the match — which is perhaps the most surreal — Reims' goalkeeper Predrag Rajkovic brought his baby son to take a picture of him with Leo.
Afterwards, Mitchell van Bergen approached Messi to have a little chat.
As the forward approached the tunnel to leave the pitch, he bumped into ex-teammate Thierry Henry.
Finally, the Reims fans asked the Argentina international to sign a huge banner with his name on it. Only then was Messi able to leave the pitch.
Here's what it all looked like.