Unable to answer "Is this a one-way street? In which direction?" – Rue Jérome Gebwiller (Alley) – https://osm.org/way/1279983949 via StreetComplete 57.1:

C'est inaccessible aux voitures.
Voie partagée cyclistes et piétons

Attached photo(s):
https://westnordost.de/p/210871.jpg
https://westnordost.de/p/210872.jpg