problem of char with form_input() and form_textarea()

Oh... I've found my answer here :
https://forum.codeigniter.com/thread-68257.html

-> if you use set_value() AND form_input(), you should use set_value('var', $projets['var'] FALSE) because both functions "escape" the value.
You can turn off html escaping in set_value, by adding a third parameter.

Thanks again to nunenthal !