It is possible to display child categories based on the last segment of the url?

If you install the useful URL-Helper add-on this will give you the ability to translate segments in your URL to category IDs. For example, once URL-Helper is installed you can access the Category ID of the last segment using the variable {last_segment_category_id} Once you have the category ID you can use the EE category tools to get your list of child categories. HTH

Thank you very much. I have installed the add on and it works, but I don’t know how to display the children categories of the category_id that I have extracted from the url.

You should be able to do this using the Channel Categories tag. See the documentation on link provided for information and examples.

I used URL-Helper and GW Categories together, and they work fine.

Thank you very much!