diff --git a/README.md b/README.md
index 8a2a0a9..2a58665 100644
--- a/README.md
+++ b/README.md
@@ -204,7 +204,7 @@ change the default without having to pass flags every time.
 
 ### 4.3. Locale shortcuts
 
-The `[general]` key `SET_LOCALE` accepts a comma-separated list of
+The `[lang]` key `SET_LOCALE` accepts a comma-separated list of
 `alias:locale` pairs. Each pair generates a function of that name at startup:
 
 ```ini
@@ -214,6 +214,16 @@ SET_LOCALE = fr:fr_FR.UTF-8, us:en_US.UTF-8
 This creates `setfr` and `setus`. Use `setlocale <locale>` to switch to any
 installed locale directly.
 
+Set `DEFAULT_LANG` to one of the defined aliases to activate that locale
+automatically at login:
+
+```ini
+DEFAULT_LANG = fr
+```
+
+If `DEFAULT_LANG` is set but does not match any alias in `SET_LOCALE`, a
+warning is displayed and no locale change is applied.
+
 ### 4.4. Prompt theming
 
 The prompt appearance is controlled by two mechanisms that are applied in order
diff --git a/doc/profile.conf.example b/doc/profile.conf.example
index 86a94c8..bcfb113 100755
--- a/doc/profile.conf.example
+++ b/doc/profile.conf.example
@@ -89,6 +89,11 @@ TERM=xterm-256color
 # creates setfr, setus, setes.
 #SET_LOCALE=fr:fr_FR.UTF-8,us:en_US.UTF-8
 
+# Alias to activate at login. Must match one of the aliases defined in SET_LOCALE above.
+# Example: DEFAULT_LANG=fr  → calls setfr at startup.
+# Leave unset to keep the system default locale.
+#DEFAULT_LANG=fr
+
 # ==============================================================================
 [net]
 # dwl: Force a specific download tool (curl, wget, fetch).
diff --git a/profile.sh b/profile.sh
index 03bae09..84b3399 100644
--- a/profile.sh
+++ b/profile.sh
@@ -258,8 +258,18 @@ if [[ $INTERACTIVE ]]; then
     trap 'timer_start' DEBUG
     PROMPT_COMMAND='set_prompt'
 
-    # Set default language
-    setfr
+    # Set default language from DEFAULT_LANG config key (set in [general]).
+    # The value must match one of the alias names defined in SET_LOCALE so that
+    # the corresponding set<alias> function exists after build_locale_shortcuts.
+    if [[ -n "${DEFAULT_LANG:-}" ]]; then
+        local _lang_fn="set${DEFAULT_LANG}"
+        if declare -F "$_lang_fn" >/dev/null 2>&1; then
+            "$_lang_fn"
+        else
+            disp W "DEFAULT_LANG '$DEFAULT_LANG' has no matching locale shortcut (check SET_LOCALE in profile.conf)."
+        fi
+        unset _lang_fn
+    fi
     showinfo && printf "\n"
     check_updates -q
     disp I "Profile version $PROFVERSION chargé..."