Without the mouse,
is there any way to select a «Barline»?
No, at present there is no way to select a barline without the mouse, but unless you actually want to delete the barline there is no need to select it: if you want to create a different kind of barline (e.g. a double barline) on top of an existing barline, you can do that with the first note following the bar selected instead. Similarly for things that are positioned above the barline, such as rehearsal marks, selecting the first note after the barline is sufficient.
Hi Alain
I can select barlines with the TAB key on my Mac here. This key ( ->| ) takes me from barline to barline. And Shift - TAB goes the other way round.
So here it works. 
Hope this helps.
Of course, you’re quite right, René. I had forgotten that!
Daniel et René,
Merci
Alain