I am currently in Franche Comte in eastern France and the meadows and verges are full of small pinkish-mauve flowers.
They are about 10 inches to a foot tall, with straight stems on which are clusters of small pale pinkish-mauve flowers with 4 petals and about 5 yellow stamens. They look a bit like oilseed rape flowers (apart from the colour) so I thought they might be a species of the brassicae family, but I do not think they are hesperis because of the leaves. They have very small alternate leaves, deeply serrated (almost needle-like) along the stems, and no leaves at the plant base. They have a sweet scent in the evening.

This is probably an easy one, but I do not have my plant books with me and my google searches have not been successful.

Well done for identifying this yourself. We have this here, high in the Lake District England, but it's nowhere near as advanced as you, but I did see some growing today.
We've just got back from a good week on Islay on the west of Scotland - saw of lots of interesting birds, including our first sightings of purple sandpiper, white-fronted geese and brent geese.