C-M-. (find-tag-regexp) is not working

[Francis Moreau]

Hello,

I have a strange behaviour with emacs23 and this key binding.

When I want to invoke 'find-tag-regexp' function with C-M-., emacs
invokes 'find-tag' instead.

However if I execute 'find-tag-regexp' manually (M-x find-tag-regexp),
it works as expected and emacs tells me that I can use C-M-. key
binding to invoke this function...

Now if I ask for a key binding description (C-h k) of C-M-., emacs
tells me:

    M-. runs the command find-tag, which is an interactive compiled
Lisp...

So it looks like when I press C-M-., emacs interprets this to M-.

Could anybody tell me why ?

Thanks