ON THE BLOCK?: Rumblings are afoot that François Pinault, through his investment holding company Artemis, is looking to sell the tony Château Latour vineyard, as well as the Christie’s International auction house. According to British press reports, the French business tycoon has hired Lazard to shop around the winery he purchased in 1993. He acquired Christie’s five years later. A Christie’s spokeswoman said the company does not comment on speculation. No one could be reached at Château Latour or at Artemis on Monday.