Following a review of video footage, Tuilagi was cited for striking Japan player Harumichi Tatekawa with his knee during the second minute of their game at Milton Keynes.
Tuilagi denied the act of foul play, but the charge was upheld by an independent judicial officer, after reviewing evidence including from all camera angles, medical evidence and submissions from the player.
The offence was deemed to be mid-range, which carries a starting point of an eight-week ban. This was cut to five weeks because of Tuilagi’s impeccable conduct during the hearing, good character and record over a long career.He had 48 hours to appeal against the decision.
The 34-year-old will miss Samoa’s final Pool B match against Scotland this weekend and will also be unavailable for his club side, Newcastle Falcons, until 10 November.
The five-week ban probably marks the end of Tuilagi’s international career.
The Manu Samoa vice-captain has played 38 times for Samoa since his debut in 2002, including four as captain, and scored 18 tries. He has appeared at the last three World Cups.
Given his age, this year’s tournament is expected to be his international swansong.
No.8 Faifili Levave has also been cited for playing the opponent without the ball and was due to appear before the judiciary Wednesday evening.