https://github.com/Beep6581/RawTherapee/issues/6452

Index: rtengine/procparams.cc
--- rtengine/procparams.cc.orig
+++ rtengine/procparams.cc
@@ -8664,7 +8664,7 @@ int ProcParams::save(const Glib::ustring& fname, const
 
 int ProcParams::load(const Glib::ustring& fname, ParamsEdited* pedited)
 {
-    setlocale(LC_NUMERIC, "C");  // to set decimal point to "."
+    //setlocale(LC_NUMERIC, "C");  // to set decimal point to "."
 
     if (fname.empty()) {
         return 1;
