Plot hole: Why on earth would a sleazeball like Adam Klaus be worried about news of a one-night stand being revealed? He'd welcome the publicity, if anything. Anyone threatening to go to the papers with news of a bit of rumpy-pumpy with him would be wasting their time.
Continuity mistake: When Le Fley runs through the house to be shown that the painting is missing, he is seen in three shots; in the first he is barefoot, in the second he appears to be wearing light-coloured mules, loafers or some other lightweight footwear, and in the third he is barefoot again. It is a little hard to see this in the second shot as his feet are moving quickly, so I could be mistaken, but it does look like he has something on his feet.