What was the rationale for reverse brake levers? The Porteur style of bicycle popular by newspaper delivery men in France in the 1940s-1960s had reverse brake levers, seen here in this diagram from an article from Bicycle Quarterly (the photo jpeg is titled rebourherseville1960.jpg): 



A bunch of manufacturers including Dia-compe used to sell brake levers that were reversed and there are also some contemporary reproductions:


Was this just purely for style reasons? I can't think of many advantages of a reverse brake lever (except style) and can think of major disadvantages (it will hook or catch on things as you move forward). What were the rationale for having brake levers like this originally? 

Period sources preferred.
If you look at drawings of old bikes, both types of brake configurations are depicted. This supports the idea that it was merely a design choice with no significant pros and cons over other configurations other than aesthetics. I suggest that it just so happens that builders in the place and time period you cited used this design because it was fashionable.

There is very limited risk here for "catching" unless the rider is literally going through shrubs (and in that situation, catching would be the least concern). Also, bizarre freak-accidents aside, no one is going to be "speared" by a reverse brake handle. Think about what would actually have to occur for that to happen.