The man was “detected upon his arrival at the Disneyland hotel where he had a reservation. Hotel security found two handguns and ammunition on him,” the source said.
A separate police source said the metal detector went off as the man passed through.
Police were called and arrested the suspect while they secured his vehicle.
They then arrested a woman, believing her to be his girlfriend, but released her after realising they had the wrong woman, one of the police sources said.
Papers found on the suspect indicated that he lived in Paris, but no further details were available about him. His girlfriend was still being sought.
A police source said preliminary investigations did not point to terrorism, and that the man had said he was carrying the guns because he feared for his safety.
Disneyland Paris, about 30 kilometres (18 miles) east of the French capital, is the most visited theme park in Europe, with some 10 million visitors in 2014, according to that year’s Global Attractions Attendance Report.
France is on high alert after a devastating terror attack in November saw Islamic State group gunmen and suicide bombers target Paris cafes, a concert venue and the Stade de France national stadium, leaving 130 dead and hundreds injured.
The bloodshed was the second major attack in France within a year, as the country has become a prime target for the jihadist group operating out of Iraq and Syria.
In January 2015, three days of terror gripped Paris as a series of attacks left 17 people dead, including an attack on the satirical newspaper Charlie Hebdo.
France imposed a three-month state of emergency after the November attacks, which President Francois Hollande hopes to extend for another three months despite fierce opposition from rights activists.