Impossible to set French language pack on 5.3.4 and 5.4 versions

Hello, I tried to get 5.3.5. as well as 5.4.0. versions on my Macbook pro (see details below), but in both cases the main application works properly, but not the translation pack in French, although I fully respected instructions.
It says it isn’t valid : “/Applications/LibreOffice Language Pack.appCe n’est pas une installation valide de LibreOffice 5.3. Exécutez de nouveau l’installeur et choisissez une version valide de 5.3 LibreOffice”
Is there any way to fix this, please?
Thanks in advance,

Le MacBook Pro (Retina, 15 pouces, mi-2015)
2,8 GHz Intel Core i7
16 Go 1600 MHz DDR3
Intel Iris Pro 1536 Mo