diff --git a/app/views/contests/show.html.slim b/app/views/contests/show.html.slim
index f8537f1..faab844 100644
--- a/app/views/contests/show.html.slim
+++ b/app/views/contests/show.html.slim
@@ -9,6 +9,7 @@
 javascript:
   async function copyExtensionUrlToClipboard() {
     await navigator.clipboard.writeText("#{message_url}?token=#{@contest.generate_token_for(:token)}");
+    alert("#{t("contests.show.url_copied")}");
   }
 
 .row.mb-5
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 6bb71b8..a4a78f3 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -133,6 +133,7 @@ en:
       add_puzzle: Add puzzle
       copy_extension_url: Copy the URL for connecting from the browser extension
       open_public_scoreboard: Open public scoreboard
+      url_copied: URL copied to the clipboard
   contestants:
     convert_csv:
       title: "Import participants"
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 7a37fd4..6dd0323 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -104,6 +104,7 @@ fr:
       add_puzzle: Ajouter un puzzle
       copy_extension_url: Copier l'URL pour la connexion depuis l'extension web
       open_public_scoreboard: Ouvrir le classement public
+      url_copied: L’URL a été copiée dans le presse-papier
   contestants:
     convert_csv:
       title: "Importer des participant.e.s"