A tribunal on Friday had originally proposed a six month suspension for 33-year-old Hermann Fuster, but this was reduced to three months on Monday by the mayor of the south west town of Agen, Jean Dionis du Séjour.
Fuster works as a visitor services assistant at Agen's music conservatory.
In a statement, the mayor said he had listened to reports and statements about Fuster that meant he felt able to "cut in half the punishment."
Fuster was given a six-month suspended prison sentence in July after the attack, which took place on June 30th in the southern town of Brax.
After the attack, he told newspaper Le Parisien that he had wanted to "express my unhappiness" to the president.
To get close to the president he had said to someone in front of him "excuse me, I would like to put my fist in his face." The person had thought he was joking so let him through.
"At first I wanted to shake his hand," he said. Then "I wanted to tap him on the shoulder. At the moment when my hand touched his suit, the guards behind me grabbed me and pulled me backwards."
"Like anyone who is being jostled from behind, I tried to grab hold of something to stop myself from falling. I ended up grabbing the shoulder of Sarkozy while trying to stop my fall."
Newspaper Le Monde reported that a union representative who accompanied Fuster at the hearing with the mayor said he "regretted" the attack and was aware of the "seriousness" of what he had done.
"The mayor took into account the different statements of support that he received. Hermann is happy to be able to get back to work because he has received support from his colleagues. For him it's a victory because work is his life," she said.