What provisions of the declaration forbid conditions that existed under the old regime?

The Old Regime was the political system that the Kingdom of France used to govern its territory. It was established during the 15th century and lasted until the 1789 when it was abolished by the French Revolution.

It was characterized by supporting the "hereditary monarchy", which meant that the right to be king was attributed to the current king's descendants. It also created the "French Nobility", which was a privileged social class that represented the Second State. The other 2 States were the bourgeois and peasants (3rd State) and the clergy (1st State).  

Article 13 of the provisions of the declaration forbade the existence of different states in the Republic. From then on, all of the citizens of the republic were required to pay taxes. Prior to this, the 3rd State was required to pay for the totality of taxes in the kingdom.