The 39-year-old owner of the drone was released from custody after the questioning on Tuesday, said Maciej Blachlinski, spokesman for police in Piaseczno near the Polish capital. The man was questioned as a witness and hasn't faced any charges yet.
Experts will examine his drone for any photos it might have taken and for any flight records to check whether it was involved in Monday's near-collision. Blachlinski said it wasn't clear when those tests would be performed.
The drone was flown on Monday, the police spokesman said, but he refused to give any further details. He could not immediately comment on the type specifics of the drone.
Interfering with air traffic in Poland carries a prison term of up to five years, while posing a threat to air traffic carries up to eight years in prison.
The incident occurred over the Piaseczno area when the pilots of the plane arriving from Munich spotted an object, believed to be a drone, pass within 100 metres (300 feet) of the plane.
Lufthansa spokeswoman Bettina Rittberger said that "a black object appeared on the right side of the plane," an Embraer 195, at an altitude of 2,500 feet (760 metres) and that the crew "supposed that this object could be a drone."
Drones, unmanned flying aircraft operated by remote control, have been growing increasingly popular across the world, posing a threat to planes. In New York, a commercial airliner narrowly missed colliding midair with a drone as it neared LaGuardia airport in May.
The biggest risk to planes from a drone is if it gets sucked into an engine and causes a stall, similar to the possible effects from a bird strike. Other threats to planes from a drone collision could be damage to critical flight equipment.
In Poland, flying drones within a 20-kilometre (12-mile) radius around airports requires special permission from air space authorities.
Drones weighing more than 25 kilograms (55 pounds) need to be registered and their operators need to be licensed, but small devices can be easily bought in supermarkets.