Unable to answer "What is the reference number of this La Poste postbox?" for https://osm.org/node/2827136405 via StreetComplete 31.3:

2 boites aux lettres :
- A5R309 : dép. 44, 49, 85
- A5R3P3 : autres dép. et etranger

Attached photo(s):
https://westnordost.de/p/39121.jpg