Messi could win his second The Best trophy after leading Argentina to their third World Cup title by beating Mbappe's France in last year's final in Qatar, scoring seven goals during the tournament and earning his second Golden ball.
Midtable Reims extended its unbeaten run to 12 games, which included holding PSG to a 0-0 draw at home in October, and was the better side in the first half.
The number of assists by a player is considered in the case of a tie for goals scored.
Theo Hernandez put the French ahead in the fifth minute at the Al Bayt Stadium. Substitute Randal Kolo Muani made it 2-0 in the 79th minute.
With Mbappe on the left flank of France's attack, he will cross paths with right-back Hakimi, the player he took under his wing when the Moroccan joined PSG from Inter Milan in 2021.
France are eyeing a second successive final, while Morocco are playing in their maiden semifinal.
France will meet Morocco in the second semifinal.
Olivier Giroud had put France ahead in the first half. Robert Lewandowski managed a late consolation for Poland.
Adrien Rabiot forced a save from Kasper Schmeichel for France.
A glance at five young strikers who could dazzle at Qatar 2022.