According to regions, 'official national' French can sound a bit different. According to social classes too, even when they try to speak a standard and half high level language.
Today the big towns French, a levelling made with help of the media, is "colorless" to me.
Before, in the standard and Oil dialects, there was a big difference between two 'a', one very open and forwards, the other very "shut" and backwards, sometimes with kind of a 'o' taste.