An independent disciplinary committee found that the 22-year-old flanker guilty of an eye-gouge on Scotland replacement hooker Ewan Ashman during the Round Four encounter.
Scotland claimed a shock 50-40 victory over Les Bleus and Jegou's indiscretion occurred in the 59th minute during the build-up to a second try scored by Darcy Graham.
Television footage showed that Jegou had his fingers around the eye area of Ashman during a Scottish maul deep inside France's 22.
At the time, it was either not seen or not deemed worthy by the television match official to alert referee Angus Gardner to the incident.
Jegou's hearing was delayed for 24 hours by the disciplinary panel as they amended the charge to include the word 'reckless' in the citing, which was upheld.
The disciplinary panel said the foul play warranted a red card.
A statement issued by the Six Nations governing body said the disciplinary committee ruled that Jegou's actions met the low-end entry point of six weeks as Ashman wasn't injured during the incident.
Jegou's suspension was subsequently reduced from six weeks to four due to his prior good conduct and disciplinary record.
"In applying World Rugby's sanctioning provisions, the independent Disciplinary Committee determined that the low-end entry point of six weeks was appropriate in light of the fact that (among other reasons) there was no injury caused to the victim," the statement read.
"In light of mitigating factors (including the player's good conduct and good disciplinary record), the independent Disciplinary Committee applied a two-week reduction in sanction, thus reducing the final sanction to four weeks.
"There were no aggravating factors to increase the sanction."
Jegou's suspension rules him out of France's crunch Six Nations clash with England in Paris on Saturday, and he will be unavailable for La Rochelle's club fixtures against Pau, Bayonne and Newcastle Falcons.
Les Bleus and Scotland are level on 16 points in the Six Nations standings ahead of the final round of matches in the Championship, and the Scots face Ireland, who are two points adrift, in their encounter in Dublin.