During the 1970's Lahner exhibited in both Paris and in California. He purchased a small villa in Vence with the proceeds from these exhibitions. From the villa's terrace he looked out over the precipitous hills that were lined with olive trees and covered in soft reflective light.

In the final decade of his career, Lahner had returned to his Impressionistic roots for inspiration, but with a bold, abstract style of expression. He produced some of the most imaginative works of his entire oeuvre.