Create interactive search filter I need to develop a search form with two differents taxonomy (taxo1,taxo2).

When a user selects in taxo1 la term, the second list has to be shown with inside only corresponding taxonomy terms.

Here is a example: if the user selects term departement in the first taxonomy taxo1 (using a select list), then a second select list (with terms from taxo2) should appear with only towns from the department previuously selected.

I can't do that with Views because filters can not interact.

Can anybody give me a way to do this?
What you are looking for is hierarchical list and can be accomplished by using these well-maintained modules below. The difference is Simple Hierarchical Select module provides a simpler implementation for dependent taxonomies [might work for your situation better]. 


  - Hierarchical select -- 
  This module defines the "hierarchical_select" form element, which is a greatly enhanced way for letting the user select items in a hierarchy. Hierarchical Select has the ability to save the entire lineage of a selection or only the "deepest" selection. You can configure it to force the user to make a selection as deep as possible in the tree, or allow the user to select an item anywhere in the tree. Levels can be labeled, you can configure limit the number of items that can be selected, configure a title for the dropbox, choose a site-wide animation delay, and so on. You can even create new items and levels through Hierarchical Select!
  
  Simple hierarchical select Simple hierarchical select defines a new form widget for taxonomy fields to select a term by "browsing" through the vocabularies hierarchy.
  The widget is available in node forms and as Views exposed filter.This module has been inspired by Hierarchical select but is much simpler (hence the name ;) ).Unlike Hierarchical select this module provides a simple widget for taxonomy terms only. As an addition Simple hierachical select works as Views exposed filter.