In one of the images issued by Sussex Police, the pair are seen with their arms round each other on the Dover to Calais route at 9:30pm last Thursday.
Megan, 15, and Jeremy Forrest, 30, have sparked a pan-European search, prompting appeals by her family in Eastbourne, East Sussex, to make contact.
Chief Inspector Jason Tingley, of Sussex Police, said: “We are releasing this photo to show Megan and Jeremy’s appearance at the time they travelled to France, as we believe it will improve the public’s ability to recognise the pair together.
“Although they entered France, it is possible that they are elsewhere now. Therefore our objectives are to identify where they are and for them to contact us, so we can bring Megan home safely.”
Mr Tingley said they were working with Interpol, a liaison officer in France and the French Missing Persons Bureau, plus other law enforcement agencies in Europe.
“On an inquiry like this, there will always be reports of unconfirmed sightings, which we will follow up. We will not comment on speculation about locations, but with public awareness being a key factor in this inquiry,
we will publicise confirmed sightings.”
The child’s school has come under fire from a charity over its safeguarding record.
Megan attends Bishop Bell C of E School, in Eastbourne. In 2009, a teacher from the school was jailed for grooming pupils.