Solution : https://service.sap.com/sap/support/notes/406692 (SAP Service marketplace login required)
Key words : 
sap system installation                      dec/20015 final installation steps                        dec0016 installation check list7 troubleshooting+===================================================================+ 1, < host>_<sid>_<inst>  de_de_iso1          bad locale, installation preparations +===================================================================+------------------<d029035 nov/01>-------------------------- english interactive subsystem, topics                                          date changed======                                          ============1 general information2 errors, sap web application server including theinstallation, final installation steps +===================================================================+-----------------------<d029695, sap web application server installation, installation documentation3 installation preparations                        nov/20014, sap note 40815                    en_gb_iso1          bad locale, required operating system locales
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