For a web GIS application, we need to get all of our data and basemaps in the same projection.
We would like to use OpenTopoMap basemap which is in Web Mercator projection (EPSG 3857) but for our web GIS app, it has to be in Lambert93 (EPSG 2154).
How is it possible to reproject OpenTopoMap easily, if possible, with open source solution to create my own webservice of OpenTopoMap in Lambert93?