Well basically it depends if you want to work in France later or not.
If so, the way to go is to study at a business or engineering school (in your case), since universities are pretty much considered lower level (in France), at least if you are not studying something very specific.
Most of these schools need you to pass an exam, but i think you can apply as a foreigner and i guess you would be more likely to get in if you apply as such.
As for universities, they have to accept anyone (though i don't know how it works for foreigners, anyway it is way easier to get in than in 'schools' because universities are not supposed to select the students).
edit: if you absolutely want to study in Paris (in the city), you probably will have to go with a university since most schools are located outside of Paris because of their big(ger) campus.