This kind of pass is specific pass sold from oversea for oversea travellers. I don t know if you can buy it from Paris.
The cost of $448 (around 300 Euros) for 4 days travelling seems apropriate and interesting as you gain in flexibity. A single ticket from Paris-Geneve is around 90 Euros (full price ticket) and Paris-Marseille around 100 Euros.
But, if you can schedule you travelling date, and buy in advance from internet (as I do frequently from HK), you can get much cheaper ticket. I did it recently and got ticket Paris-Toulon for only 22 Euros (1 month before departure) when normally the same ticket (same day, same time) was sold at 98 Euros. A friend of mine would like to join the trip in last minute had to pay the full price ticket.
