A Century of Chess: Podebrady 1936
A real high-water mark for Flohr, making the case (if more evidence were needed) that he was fully deserving of a world championship match. The tournament was a horse-race between Flohr and the recently-dethroned world champion Alekhine. Alekhine did his part scoring +8-0=9, but Flohr was slightly more lethal against the bottom half of the crosstable and finished a half-point ahead.
Flohr played in his usual crisp positional style, with his eye for witty tactics.
Historically, chess champions have tended to be particularly dangerous just when they have just lost their title. Earlier in 1936, Alekhine had finished shared first at a small tournament at Bad Neuheim and clear first at a slightly stronger one in Dresden. But, here, Alekhine was so furious at being unable to overcome Vladimir Petrov in the last round that he offered a draw and stormed out of the playing hall without waiting to see if Petrov would accept it ... even though Petrov actually had a slightly better position.
It's a theme of the 1930s to come across a number of players I've never heard of who turn out to be terrific. The sensation of the tournament was the Polish master Paulino Frydman. Frydman opened the tournament with eight points out of the first nine, including a six-game winning streak, but couldn't maintain the pace. The tournament doubled as a Czech championship with Jan Foltys taking that title and finishing third overall, ahead of several far more famous players.
Sources: There's not a huge amount online about this tournament. As usual, I am indebted to the chessgames.com page. Edward Winter here seems to dispel a persistent myth that Frydman suffered a nervous breakdown.