How to give users with role Role2 the right to edit only user accounts with role Role1 I need to make a user edit users that have a specific role.
In fact we have two user roles here.


Role1 -> is able to edit a particular kind of node
Role2 -> is only able to  administer users with the role "Role1". 


My question: how to give users of Role2 access to edit only user accounts of Role1?
You may want to try Administer Users by Role module.


  This module allows site builders to set up fine-grained permissions
  for allowing "sub-admin" users to edit and delete other users — more
  specific than Drupal Core's all-or-nothing 'administer users'
  permission. It also provides and enforces a 'create users' permission.


One of the extra permissions that this module provides is

Edit users with custom roles - Allows editing of any authenticated user with the specified role.