French champions Montpellier said on their website that the decision was made by the French football federation's Appeal Commission.
The reduction in the ban, which started on November 23, means Jeunechamp will be eligible for the final round of matches of the Ligue 1 season on May 26.
Jeunechamp, 37, had an argument with a L'Equipe reporter over a story published in the newspaper before the 1-1 league draw at Valenciennes on November 17.
Montpellier apologised to the reporter and condemned their player's behaviour.
- Sports & Recreation