Custom redirects doesn´t work as expected - htaccess

[Belletage]

Hi,
I´ve some pages (sidebar-text), which are part of others
and I want to redirect their slug-names to the fitting page.

I add the htaccess with

Code:

RewriteRule /?([A-Za-z0-9_-]+)\.html$ index.php?id=$1 [QSA,L]

Redirect /sidebar-slug.html http://www.domain.tld/slug.html

but when I call the side, it happens something like that:
domain.tld/slug.html?id=sidebar-slug

and I see my sidebar-text. :-|

whats the problem there? The RewriteRule - but I need it.
(it works on an other CMS - but I´m not used to server/htaccess-stuff ...)

thanks for help,
best, Bell.