Retrieve new user right after registration

I have a function in which I will use the new user’s infos to do stuff. I know that after a successful registration, user get redirected to wp-login.php with checkemail=registered as arguments…that’s good for me to know that the registration is done.

However, I don’t know how to get the information from that new user.
How can my function be called right after a user completes a registration?

I’d like to avoid having to send a query to the database asking for the last inserted user in order to avoid conflicts and such.

Thank you!