Here it is allowed to ride bicycles on sidewalks. It is not encouraged - the law says cyclists should ride on the road, or must ride on bike path/lane; but if there is no bike path/lane and the conditions make it too dangerous or impossible to ride on road, you are allowed to ride your bike on sidewalk, provided you don't interfere with pedestrians which have priority there. Since the distinction of what constitutes "too dangerous" is arbitrary, and bike infrastructure is rare in this city, many casual riders choose to ride on sidewalk at all times.
That said, it is allowed to ride through crosswalks, but only at speeds that don't exceed typical pedestrian speed. This amendment came into effect 3,5 years ago, but I still see people who dismount and walk their bikes through crosswalks quite often. Drivers seem to have learned this rule by now (which wasn't the case in the first couple years).