The allegation surfaced in Le Matin Dimanche which cited the father of a girl who was seriously wounded in the crash late Tuesday as the group returned from a skiing holiday.
"My daughter said the last thing she remembers is that one of the teachers went to the driver with a DVD," the paper reported the father, who was not named, as saying.
Swiss prosecutor Olivier Elsig told the ATS news agency that "the screens lit up and the children saw the menu for a film."
But he said there was no testimony about the presence of another person in front of the bus who might have distracted the driver.
Investigators said the only thing that had been established was that all six adults were sitting in the front of the bus.
Elsig said Swiss investigators would travel to Belgium to interview the surviving children for more insight into the tragedy.
The victims included Belgian and Dutch school children aged 11 and 12 years old.
It is believed that the coach carrying 46 children, four teachers and two drivers clipped a kerb before it slammed into the wall of a tunnel.
Investigators are still looking into the theories that technical problems with the coach or human error caused the crash. Alcohol, speed and driver illness have so far been ruled out as the cause of the crash.
A service of remembrance will be held Wednesday in the Belgian town of Lommel, which was home to 15 of the children and two of the adults killed.
Burial services, however, will be held privately.
The king and queen of the Belgians, Albert II and Paola, along with Dutch Prime Minister Mark Rutte, and Dutch Prince Willem-Alexander and Princess Maxima will attend the service.
They will also attend a service of remembrance Thursday in Louvain, their offices said on Sunday.