They'll need to exist in both places:
/includes/languages/french/html_includes/define_page_2.php
and
/includes/languages/french/html_includes/YOUR_CUSTOM_TEMPLATE/define_page_2.php
Right or wrong, the first one tells the editor that a file by that name should be listed.
The second one, in the custom folder, is the one that is actually loaded by the editor.



