@Nicolas-AULANIER 16Gb is plenty for maps… My wife has the Race (Steel / 16Gb) and we have the same maps loaded (I have the Vertical Ti / 32Gb).
Although map sizes are different for different counrties etc. To give you an idea of how much you can hold with 16Gb.
ALL - ITALY
ALL - CROATIA
ALL - AUSTRIA
ALL - SLOVENIA
ALL - NEW ZEALAND
UTMB SECTION - FRANCE
UTMB SECTION - SWITZERLAND
The app makes it easy to download and set maps as needed. I quite like the approach. And the app automatically highlights the map closest to you, so you can adjust on the fly. The watch internal memory specified is only used for maps, so you can be confident that even 16Gb has you covered for even the biggest adventures.