@Gabi Wehler, kia ora
I have four hard copy guides and two map sources I use for Le Puy to the Pyrenees. These are:
Hard copy
1) Cicerone - Alison Raju - (1) The way of S James, France - step by step
2) Miam Miam Dodo - Clouteau - (1) Le Puy-Cahors (2) Cahors-Roncevaux (3) Cele variant
3) ffRandonnee - ... - sentier vers ... Compostelle (1) Le Puy-Figeac (2) F...-Moissac (3) M...-Roncevaux
4) Michelin - ... - 161 Chemins de Compostelle Le Puy-Saint-Jean
1) above was detailed and assumed you knew exactly where you were and would have it out to refer to at each turn. This may have been useful when the GR waymarks were not so frequent.
2) and 3) above were, for me more useful. Together they weighed about 800 grams. I much preferred the maps in 3). Long before leaving home I scanned for use on my tablet the map sections as these would be the most use for me. I found I seldom referred to them.
4) I purchased from a corner store in Nasbinals (end of day 4 for me). This weighs 90 grams and easily fitted in a largish pouch slung across my chest between the shoulder straps. The maps are, for me, easy to read on the go. Along with the other stuff it became my regular goto on the way. (For Spain I purchased the companion Michelin 160 Saint-Jean-Compostela)
Maps on the tablet
I use a tablet (phone included - weighs about 800 grams) as it is easier for me to see a big picture and close-up detail than on a normal sized phone. The things below cover the world, so you can also scroll etc to see what is recorded near you home. 1) and 2) are on-line browser apps. 3) is an offline app.
1)
Hiking.WayMarkedTrails.org That link shows my first day from Le Puy to Saint-Privat-d'Allier. Scrolling back and moving the screen you can see not only Le Podiensis but any other walking route that has been mapped. Click on "routes" (bottom right corner) and you can select a route and see what heads-up details have been included. At the foot there are three icons with the middle one being "locate me".
2)
OpenStreetMap,org This is a more general purpose map (Hiking... gets its data from here)
3)
OsmAnd is an app for Android devices. Within the app, and when on wifi, you download maps for the country/region that you need. As well as details there can be contour lines, hillshades and slope additions to download. All of New Zealand is one download while all of France is in 13 regions. When underway I just start the app and it can locate where I am automatically. In a car it can be used for turn by turn directions.
Be please to chat, as you wish.
Kia kaha, kia māia, kia mana'wa'nui (be strong, confident and patient)