How to redirect to a specifi page of a view?
The solution has two parts:
1. The button that takes to my form in 'Add' mode was coded this way: &lt;a href="/sel/service/add?destination=services" class="form-submit"&gt;Ajouter&lt;/a&gt; (/services being the first tab I mentioned).
So I removed the ?destination=services
2. Looking at the 'Routes info' provided by Devel, I got that:

So i changed my code to $form_state-&gt;setRedirect('view.services.page_2', ['arg_0' =&gt; $iSeliste]);  (thanks to the last comment of this page)

And now it works!