The flight landed safely in the Italian capital as scheduled, Alitalia said in a statement. All 131 passengers aboard flight AZ329 disembarked safely in Rome.
"A clearly agitated passenger attacked a flight attendant, asking that the flight be diverted to Tripoli," Alitalia said.
"Thanks to the prompt intervention of attendants, the aggressor was immobilized and (kept) in his seat, and the flight continued on to Rome," where it landed at 9:55 p.m. (1955 GMT) as scheduled, the airline said.
Alitalia didn't identify the passenger. The Italian news agency ANSA reported that he was a middle-aged man from Kazakhstan with no criminal record. ANSA said the man had brandished a nail-clipper against the flight attendant.
Police took the man into custody for questioning at Rome's Leonardo da Vinci airport, Alitalia said.
Alitalia said the female flight attendant was checked by staff at the airport's first-aid office as a precaution but she was reported to be unharmed.
The man's motive was not immediately known. Italian police were in contact with French authorities over the incident, ANSA said.