The plane coming from the Slovenian capital Ljubljana landed at Cologne-Bonn airport at about 10 PM IST yesterday.
Airport authorities said in a statement that the 151 passengers on board disembarked the plane using emergency slides and were taken to a transit gate where they were checked by police.
German news agency dpa reports that police also destroyed a piece of baggage that couldn't be assigned to anybody on board.
Take-offs and landings were suspended for three hours, causing 10 flights to be diverted to other airports and delays to over a dozen more.