Shavit,your edit is wrong and is what gives him the errors. %N is used only to retrive the name from the client index without declaring any strings.
%s is used to retrive the name from a string, in this case from decl String:name[MAX_NAME_LENGTH]; and GetClientName(tankclient, name, sizeof(name));
PHP Code:
PrintToChatAll("[HP TANK] Il reste %N HP a (%d).", name, g_iLastTankHealth);
should be
PHP Code:
PrintToChatAll("[HP TANK] Il reste %s HP a (%d).", name, g_iLastTankHealth);
TheTwistedPanda also showed a better, example on page 1 which I'd recommend using instead.
https://forums.alliedmods.net/showpost.php?p=1757501&postcount=9