I've just produced a htaccess file and joined the next

RewriteEngine on
RewriteRule ^/profile/([0-9]+)\.html /profile.php?id=$1

This really is giving us a

500 Internal Server Error

Any ideas why?

Thanks

make use of this inside your .htaccess file

RewriteRule ^profile/([0-9]+)\.html$ /profile.php?id=$1 [NC,QSA,L]