Is this abutilon vitifolium (with saucer shaped purple flowers) or one of the 'bell shaped' ones with different colours?
The former is much hardier, but if it is frosted, the best you can hope for is for it to resprout from the base.
In a pot it is more likely to have been frosted right through unless you protected the pot, depending on the temperatures this winter in Wiltshire (where we used to live before coming to France).
Don't do anything until any new growth appears, and that would be a good time to repot completely with some good compost to give it a boost and some nutrition to get going again.
When things get knocked back by frost they can take a long time to start going again so don't be impatient. Only give up if there's nothing at all by late June or early July.