From Monday 6 April 2020, any person travelling between the UK and France (regardless of the nationality) must be in possession of a fully completed form to confirm if their journey is necessary.
International travel certificate to mainland France : to be found here
As from Thursday 28 May 2020, this form also includes a sworn statement of absence of Covid-19 symptoms.
If the passenger does not have access to a printer, please advise to hand-write the wording of the form on a blank piece of paper, sign it and add their home address on the back, as they may be asked to show them.
Failure to do so may lead to a fine from the French authorities.
Please note that at this time, UK and non-EU citizens can continue to travel back to the UK.