The last representative assembly before the Revolution was the meeting of the Estates of the Pays d'Etats in 1614. This of course was a vestige of medieval practice where the king made his case for his policies, the estates advised on state (and other) matters, and agreed to financing over what the king could realize from his royal estate revenues.
At that time, France was in the middle of another period of civil-religious turmoil, and Louis XIII and the "Barbons Gris" had had enough of obstruction and having to get consent....times had changed, the political situation was dangerous, and other, more "absolutist" methods were devised (often by extra-legal means). It took a long while, but by the time Richelieu was secure in power, and the Huguenots supressed, France was beginning to be a more "absolute" monarchy. Of course, this required the cooperation of the nobility, and that was not certain until after the Frondes of 1648 to 1652.
I do not think we can think of the Estates as democratic institutions as we understand them. They were "representative" it is true, but only of the most influential groups of Nobles, Towns, Clergy, and a very few wealthier non noble land owners. The 17th century movement toward stronger central authority with available financial means and standing military forces came out of all the turmoil and conflict of the religious wars, counter reformation, the Thirty Years War, and noble rebellions (and not just in France). Representation became an agent of instability and was to be avoided.
Since "absolutist" rule could not have been done without the cooperation of the nobility and those who basically bought their way into the nobility, the "middle class" were cut out of the picture until all the pressures and abuses of the ancient regime could not be supressed. That is when that middle class revolutionary thing happened that the French have been fond of ever since. :-)