Both Sotheby’s and Christie’s are holding significant Impressionist and Modern evening sales in London this week. “We’re seeing a very strong market for top quality Impressionist paintings this summer,” the vice chairman of Impressionist & Modern Art Worldwide at Sotheby’s, Helena Newman, said.

On Wednesday, Sotheby’s will put up Monet’s “La Plage à Trouville” expected to fetch between $14 million and $20 million. “It’s an iconic work,” Ms. Newman said. “Monet was exploring the effects of the wind and the light on the water, all quintessentially Impressionist effects.”

Monet completed his painting in 1870 while vacationing with his wife and son at the tony French resort town of Trouville.