A French military official said the soldier was hospitalised but is not in life-threatening condition, and that the reason for the attack on Monday is being investigated. The official was not authorised to be publicly named.
Authorities don’t suspect terrorism as a motive at this stage, according to the national counterterrorism prosecutor’s office.
The soldier was among thousands of troops serving in the Sentinelle force for France’s domestic security, created to guard prominent French sites after a string of deadly Islamic extremist attacks in 2015.
Soldiers in the Sentinelle force have been targeted in the past.
French Interior Minister Gerald Darmanin posted on X that the soldier had been patrolling at the Gare de l’Est train station in eastern Paris, and that the assailant was detained.
Paris is deploying around 30,000 police officers each day for the Olympics, which runs from July 26 to August 11, with a peak of 45,000 for the opening ceremony on the Seine river.
About 18,000 members of the military are also helping ensure security.