I am sorry, i do not speak or write French, so i’ll do this in English.
If i understand you correct, i think you might like the format card in the Better Logic Library App.
[APP][Pro] Better Logic Library - For Users - Apps - Homey Community Forum
it has a Format card which gives parts of the date exactly how you want it, based on your locale settings and timezone (configurable through the settings):
(You can type anything you like it in and select the top one, which is what you typed).
Now, this can be placed into variables directly:
*Set [variable] to BLL Expression cards
Press execute to create the variables and tokens.
Now, to get this back to a HH:mm value, u can use this one: Execute Expression as Tag:
"[Hour]".padStart(2,'0') + ':' + "[Minutes]".padStart(2,0)
*Watch the double-quotes 
This will result in the time as usual:
N.b.
Update to version 2.3.11 of BLL (in test now) to be able to create new variables through the expressionflowcard and resolve a bug where tags are not filled with a value at the first creation.
