Want to plant some plumbago in other spots too, how to start new plants
It sounds like you are talking about the perennial groundcover plumbago, since the cape plumbago is not hardy in your zone 8. You can propagate by division and stem cuttings. These articles should help:
https://hgic.clemson.edu/factsheet/perennial-leadwort/
https://www.gardeningknowhow.com/garden-how-to/projects/rooting-plant-cuttings.htm
Saw this plant when in a visit to South of France, will I be able to grow this shrub in my area ?
This looks to be a plumbago. Plumbago shrubs can grow in your area, but they require some attention due to the cooler climate. While they thrive in warm, sunny locations, the plant is not frost-hardy and may need protection during the winter months. Growing plumbago in pots allows for easier overwintering indoors, where temperatures remain above freezing. When planted outdoors, ensure they are positioned in a sheltered spot with well-drained soil to encourage healthy growth. Regular care during colder seasons will help maintain their health and appearance in this region.