"Half seven" is in fact 6:30 for Russian and German speakers
In German and Russian, half of an hour actually refers to half of the previous hour. For example: if somebody tells you to meet up at half eight, this would mean 7:30, not 8:30! Very often, German and Russian speakers translate this expression directly from their mother tongue when speaking a foreign language and end up messing up everybody's schedule. So when you are invited over for vodka or schnaps at half 7, be careful not to show up an hour late!