Can I search "Added By/Modified By" with a contact ID instead of a name?
Bonjour. I think you are using the field in the Change Log, Modified By (Added by) - ie 'Journal of Change' is your translation of the French version of 'Change Log'.
You are right, currently it is just used as a 'text' field. So Advanced Search is not going to help you.
And the field is not currently available in Search Builder either.
And there is no Custom Search for this.

So, if you have developer/funds is to add the feature to one of the above.

Or create an extension that does the above automatically.

The only other thought is that you could consider another approach, such as, if you are using Drupal you could have your team 'add' contacts through Drupal Webform - and create a Relationship between them. The benefits would be that you could then


search by the Relationship and then create a Smart Group
use the Permissioned Relationship extension so that user 'Jean' could only see contacts that they added.


Hope some of the above is helpful.