There isn't any magical bet, you can always loose, but seems safe betting on Germany win against Poland.
Why is that a safe bet? Odds have been dropping on Germany a bit even though the Public is favoring them. Could be a close match between these teams. The most likely result is a draw imo.
It has been draw in the last game this 2 teams played, but I think tonight will be different, Germany will nail a win an advance to the next phase of the Championship as leader of the group, Poland merely beat Ireland 1-0 in the first game so I don't think Germany will have any problem to beat Poland tonight. But as we have seen before a lot of surprises have already happened in this Euro 2016 so far. So there's nothing as a safe bet for the moment.