Police carrying out checks at an airport in southern Germany discovered several school-aged children travelling ahead of the holidays.
Reports concerning 10 families have now been sent to education officials in Bavaria, German media report.
It is believed the families caught at Memmingen Airport were trying to avoid travelling at the peak holiday time, which can be a lot more expensive.
In Germany parents are legally obliged to send their children to school.
The Memmingen families were allowed to fly off on holiday despite the questioning, a German police spokesman told the BBC. "It would have been disproportionate to take the children back to school, as the families had paid for their holidays," he said.
The Spiegel news website reports that the parents now have two weeks to explain why they took their children out of school. If the reason is not good enough each family can be fined up to €1,000 (£876; $1,177).