numeric-pad 0 key-command behavior

A key cannot be assigned as a sequence of key commands within Logic, and there isn't a command for exactly the function you want. However, here's a neatly-grouped bunch of key commands that can offer you the functionality you want:

1. Assign numeric keypad ENTER to key command "play"
2. Assign numeric keypad 0 to "stop"
3. Assign numeric keypad "." to "•go to position"

I think this combination of keys will give you the most flexibility. It would be a piece of cake to get your sequence to start from bar 1 (or any other bar for that matter):

hit 0
hit .
hit 1
hit ENTER

That key sequence would take a fraction of a second to execute.

The zero and/or the "." will function as normal for numerical entry! After a value is entered, they will invoke the various key commands you've assigned.

There are numerous other Global key commands available that might better serve you, but the above is my suggestion.

As far as your using a French keyboard, this should, theoretically, make no difference as to whether or not key commands work. Having said that, there are many bugs associated with the Key Commands window, and some key combinations won't work, and F14 and F15 by themselves won't work for anything. But you shouldn't have any problem using the numeric keypad to work.

If you're having trouble getting key commands to work by "key label", try programming them by "key position" instead.

"rewind to top" (what do you mean by "top": the beginning of the song?)

The built-in command that comes closest to this is "Stop; goto last play position"

You can probably assign this to the "0" key -- try assigning by Key Label and by Key Position. If neither one works, that's too bad, but assign it to a different key and move on...

Just hit "0" twice. The first hit will stop playback, the second hit will jump you back to the start of the song.

The numeric-keypad 0 key is both Stop AND Rewind to Beginning , though it does not do both in one keystroke. If the song is playing 0 will stop playback. Hitting 0 again will rewind to the beginning of the song. I use it often.

hit 0 - hit . - hit 1 - hit [enter]

Whichever 4-key sequence I'd pick will always be less
convenient than a single key, ever... Am I wrong when
I believe the 0 key should stop | rewind to
top? Does it do that for you? How did you program
that?

See if you can find a third-party program that will allow you to define "hot keys" outside of Logic. I'm sure I've seen programs like this. If this is a viable option, my thinking is that you could program a key as "text" which is equivalent to a string of letters, where each letter represents an individual command that Logic will respond to (as programmed in Logic's key commands window). In essence, you'd be creating your own macro.

Again, not sure if this is a "real" option, but might be worth checking out.

The zero and/or the "." will function as normal

for numerical entry

Not on a French keyboard, unfortunately:
there's a "," instead of a "." and I didn't find a
way to change it.

Then use "," instead of "."

there isn't any problem with french keyboards,
after initializing my key commands i lost that 0 key function too.
You don't have to add the key command on your own,it's there when you install logic.(if i remember well)
the key command that you can use instead is> play from the beginning(add whichever key you like there) but it doesn't stop at the beggining first as it used to ,it just starts playing from the beggining of the song.
Anyone out there with a better solution will be very welcome.