Thank you to both of you. The two genius are really close. Lorene, what kind of Silene do you think it could be ? I'll try to post some new picture (close up) soon to have a better idea.
I'm with Harri and Ron on this Saponaria. Common name soapwort. http://www.deerxlandscape.com/cgi-bin/webc.cgi/st_prod.html?p_prodid=87757&p_catid=98
Up close and personal, that's Saponaria officinalus. It's lacking the characteristic rounded ovary for Silene.
Can I just chip in to say it is the double white form. So Saponaria officinalis Alba Plena. http://www.hardys-plants.co.uk/product.asp?plant=1871 It is hard to find decent pics on www for the double white one. Saponaria officinalis Rosea Plena is more common. http://www.google.co.uk/images?hl=e...=UTF-8&source=og&sa=N&tab=wi&biw=1242&bih=529
One asked about here is pale pink, one shown at your link is pure white. Many other "white" forms of normally colored flowers are really pale pink or pale blue etc.