Q:

Regular expression for Url rewriting php

I'm using URL rewriting with Wamp but I don't find the correct regex for my needs. 
I'd like to transform http://localhost/site_artisans/site_artisans/peintre-annecy.php in http://localhost/site_artisans/site_artisanspeintre-annecy.php (remove the slash between site_artisans/site_artisans and whatever is after). 
I thought of :
RewriteEngine on
RewriteRule .*site_artisans/site_artisans/.* site_artisans/site_artisans [L]

(Unknown number of characters before and after and slash removed). 
But this doesn't work. 

A:

Try 
RewriteEngine on
RewriteRule .*site_artisans/site_artisans/(.*)  site_artisans/site_artisans$1 [L]

I tested it on http://martinmelin.se/rewrite-rule-tester/ and I believe the result is what you want.