The 26-year-old second-row forward hit Barclay with his shoulder in the 16th minute of France's 32-3 win in Nice.

The disciplinary hearing in London, ruled that "the foul play was intentional, the offence took place at considerable pace and with considerable force to the opposition's head such that the player sustained an injury."

The World Cup in Japan starts on September. The ban means that Grabrillagues, who has 13 France caps, will be out until October 7, by which point France will have played three of their four pool matches with only the potentially pivotal game against England on October 12 in Yokohama remaining.

The French Rugby Federation are considering an appeal, vice-president Serge Simon told AFP.

Last week, All Blacks lock Scott Barrett received a three-week ban for a shoulder charge into the face of Australian back row Michael Hooper on August 10.