Here is new information published 21 January in French re rules/regulation as of 24 January for travel between France and Spain.
Le passe sanitaire mute officiellement en passe vaccinal en France, Ă partir du 24 janvier. Ce qui complique un peu les choses pour voyager en Espagne et
www.equinoxmagazine.fr
The raw Google translation follows:
Do I need a vaccination pass to travel between Spain and France?
By Maréva Laville Posted on January 17, 2022 Updated on January 21, 2022

The health pass officially changes to a vaccination pass in France, from January 24. This complicates things a bit for expatriates who would like to return home. Will they be able to get on the bus, take the train? Manual.
Trains, planes, buses and even carpooling. Interregional transport in France is subject to the vaccination pass. The only exception is reserved for compelling reasons, family or health. In these cases only, a negative test will allow access to these transports. But to cross the border, there are differences.
A European QR code
The health pass has two codes. One for activities, the other for borders. The first will turn into a vaccination pass, and will apply the new validity periods (seven months until February 15, then four months to do its reminder). The European certificate, used to cross borders, is still valid up to nine months after its last dose.
Since January 17, negative antigen, PCR or self-tests are no longer enough to enjoy activities, or travel on certain transport. From the age of 16, the age of "vaccination freedom", all French people will have to justify their full vaccination. From 12 to 15 years old, the health pass will still be required.
For more convenience, the QR code received during the last vaccination can be added to the French TousAntiCovid application. Once the code has been scanned, the certificate can be used for activities and for borders. Surprisingly, the one dedicated to activities is essential for certain transport, crossing the border.
By bus: no boarding without a vaccination pass
In particular, you will have to show your credentials in the coaches departing from or heading to Barcelona. “Passengers from Spain to France will need to present proof of vaccination, converted to European format,” says Charles Billiard, communications officer at Flixbus. No Flixbus routes exist within Spain. Travelers leaving from the Iberian Peninsula therefore necessarily go to France. And that is also accompanied by the application of French measures.
Same story with competing buses, BlablaCar. Whether the departure is in France or Spain, the vaccination pass will come into effect, as the health pass had been before. It will be checked before boarding.
By train: obligation for journeys in France
The question still remains unanswered concerning the rail. According to the legislative text, the vaccination pass will be in force on long train journeys, said the Minister of Transport, Jean-Baptiste Djebbari. But on the question of a mandatory presentation for boarding, the SNCF is still awaiting instructions from the ministry.
The plane and the car are not affected
Flying to France will not pose the problem of the vaccination pass. It only applies to flights within France. Between the Iberian Peninsula and France, the way is therefore free, subject to having the European certificate, i.e. the health pass that we already know. Proof of vaccination, negative test, or recent Covid will therefore suffice.
When the car, the steering wheel can be serenely taken. No vaccination pass request is applied for this mode of transport.