set the pathPrefix

gatsby-config.js

 module.exports = {
+  pathPrefix: `/froggit.fr`,
   siteMetadata: {
     title: `Froggit`,
     description: `Speed up your GatsbyJS development workflow. Designed as a set of opinionated and advanced themes and starters using MDX and Theme-UI. Incorporates gatsby-theme-catalyst-core, gatsby-theme-catalyst-header-top, and gatsby-theme-catalyst-footer.`,