@Helena Litherland
My experience is from 2018 and obviously Covid needs to be taken into account now.
Word of mouth is quite useful in France. Ask your host to recommend the next place.
The tourist office in France is usually
very helpful too and in smaller places the Mairie also. There is really quite a lot of pilgrim-oriented accommodation.
The Diocesan Offices in Arras have cheap accommodation.
In Reims Cathedral there is a table with members of the local pilgrim association waiting to help you. If they are not there I feel sure there will be lists left behind. And they will be happy to phone ahead for you. It is a crossover point for a camino route. It is quite word-of-mouth for the next three or four days from Reims in private houses/schools/mairie.
In Chalons-en-Champagne, (after Reims) in the large parish church, Notre-Dame-en-Vaux Collegiate Church (not the cathedral), there is an office there too which will help you with accommodation. It is another crossover point for a camino route.
Another thing to note, I would say, is that you do need to make contact before you go to a place especially in northern France. The numbers of pilgrims is so low, that they will not be waiting for you on the off chance, as on the Camino. But if they know you are coming you will generally find a great welcome.
A most unusual place I stayed was an activity centre for primary school children, 'Croq Loisirs' in Dampierre-sur-Salon. You need to go to the tourist office first.
I kept a list of accommodation but never finished it but you may find it useful for the first month. It is here:
http://walkingtim.com/accommodation/ Sorry for the formatting also! My attention to the blog faded, although my walking continued on as far as Thessaloniki.