He was shown red after a bunker review for a high tackle on Caelan Doris, having earlier been given a yellow for a high hit on Andrew Porter.
A panel found the 31-year-old guilty of two acts of foul play and decided they merited four and three-week bans.
But it deemed it "disproportionate" for the bans to run consecutively.
Willemse has therefore been banned for four weeks, which can be reduced to three if he completes 'tackle school'.
Scotland, who won their Six Nations opener against Wales, host France at Murrayfield on Saturday.