Hi @idefix37, yes, this is where radar from MeteoFrance radar meets radar from MetOffice.
This is what source data from 2025-05-26T12:00Z (around the time of screenshot) and resulting composite look like:
uk_fr.gif
The data is unfortunately very different, especially over mentioned Brittany. Maybe due to different calibration or different post-processing done by above mentioned organizations.
The only difference I see in resulting composite is that data from Jersey radar (orange dot on the map, located 49.17721N -2.22393E, part of both data) is wrongly cut off from the MetOffice (UK) composite.
I will have to investigate the reason further.