Sidebars
I use in functions.php :
function build_taxonomies() {
register_taxonomy( 'thematiques', 'post', array( 'hierarchical' => true, 'label' => 'Thématiques', 'query_var' => true, 'rewrite' => true ) );
register_taxonomy( 'federations', 'page', array( 'hierarchical' => true, 'label' => 'Fédérations', 'query_var' => true, 'rewrite' => true ) );
}
I'd like to have a custom sidebar in taxonomy-thematiques.php

Comments
we don`t know if your php skills are good because this is not easy thing but we`ll try to explain...
Your file, you mentioned above taxonomy-thematiques.php, should look similar to what we paste below: And also what you need to do is go to functions/theme-head.php and replace below code:
if( function_exists('is_bbpress') && is_bbpress() && is_active_sidebar( 'forum' ) ){
with:$classes = ' with_aside aside_right';
}
if( function_exists('is_bbpress') && is_bbpress() && is_active_sidebar( 'forum' ) ){But as we wrote above this is not easy thing and you need to study those files and code very well to understand how this works exactly.$classes = ' with_aside aside_right';
}
if ( is_page_template( 'taxonomy-thematiques.php' ) ) {
$classes = ' with_aside aside_right';
}
if ( is_tax('thematiques') ) {
$classes = ' with_aside aside_right';
}
Thank you for your advices.