Go to Product choice: am 1,93m tall and 82kg with rather thin. Have long wrestled with me (M or L) and initially chose L, there was to read that the Puma jerseys are rather tight cut. But it was a lot to me (!) Too far, though length and shoulder width fit. Now I M and fits perfectly, nice body contoured and still long enough. Though: I would 4kg more would tweak it ;-)
On the Puma site (48/50) and L (52/54) is specified for M. In my opinion, this is not true all because somehow missing an intermediate size for normal weight ...
To buy at amazon: as usual quickly delivered and the return of excessive jerseys was a breeze. And the price is an absolute hammer. Whatever the reason, but Amazon can offer the jersey significantly cheaper than the BVB fan shop. Nevertheless, everything is original, do not worry!
Finally: full marks, now the second half of the season to go!