Anyone who knows Paris is unlikely to be surprised by the statistics. Suburban lines in the north an east are significantly more dangerous than those in the south and west, Paris Nord is the most dangerous mainline station and Chatelet-les-Halles tops the list for metro and RER interchanges.
There are some oddities, however. Paris-Est has a higher total of thefts than Paris-Nord but those at the Gare du Nord are far more often violent. Nation and the Gare de Lyon both show high levels of violent thefts but don't figure on the list for non-violent thefts and bag snatching. (Nation is the only station where I've ever caught anyone trying to pick my pockets, but when I turned around and caught the guy in the act he just apologised for "bumping into"me.) Meanwhile, at Montparnasse and Saint-Michel, you might lose your wallet but are unlikely to get hurt in the process.
The figures for Chatelet-les-Halles, with 409 violent thefts and 1245 non-violent, particularly stand out. That's an average of more than one violent and almost 4 non-violent robberies per day. On the other hand, they need to be put in perspective. The metro carries more than 4 million people per day, while the RER has 2.7 million passengers. Even standing in one of the city centre stations at rush hour, with trains with a capacity of over 1000 passengers going by every one or two minutes, that's hard to imagine. I haven't done the exact maths, but a rough estimate suggests that in fact the chances of being victim of a crime at any of Paris's stations, or at least of a crime serious enough to report, is actually extremely low. Here's hoping I'm right!