Redirect problem in multi-lang site

Question

I have developed a multi-language site, all necessary steps are taken in regard with plugins, menuitems and its associations, modules etc.
The language-switcher module works perfectly, but yet, when I login in French language, I am redirected to English part and this is while I already fixed redirect files in both French and English mods.
The same with login menuitems, also French and English login mods appear only on French and English pages.

What could be the problem?
_{Joomla version is 3.8.1}

Answer 1

Here is the solution to what I asked:
To redirect to the right part of the website, in plugin User group named joomla under OnUserLogin event method add the following Code:

$app = JFactory::getApplication();
$app->setUserState('users.login.form.return', $options['return']);

I myself did not reach this answer, I learnt from Sergey Onichshenkov Everything is working fine now.

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Update:

Also to complete the answer , in case of joomla update, the code shall be gone, in order to get rid of copy and paste the code again, you may develop a custom plugin under the group User and design it as what is told in the initial answer.