European Schuko adaptor which switches the Live and Neutral connections.
This adaptor will most likely be required when travelling in France as there is no standard as to how the French sockets are wired up. If the UMC shows a constant red light once plugged in, then it is likely to be due to the Live and Neutral presented the wrong way round. This adaptor corrects the inversion allowing you to charge.
This adaptor plugs directly into the power socket. You then plug the Schuko adaptor into this to allow connection to an extension lead or directly to the UMC.