The Lisbon Treaty establishes a legally quite new European Union. This is a Union in the constitutional form of a supranational European State:

The Treaty gives this new Union a State Constitution which is identical in its legal effects to the EU Constitution that French and Dutch voters rejected in their 2005 referendums.  It does this by amending the two existing basic European Treaties, the "Treaty on European Union" (TEU) and the "Treaty Establishing the European Community" (TEC). The former retains its name, while the latter is renamed the "Treaty on the Functioning of the Union"(TFU). 

These two amended Treaties become the de facto Constitution of the new Union which they constitute or establish, although they are not called a Constitution. The EU has thus been given a Constitution indirectly rather than in direct form, as had been proposed in the Treaty which the peoples of France and Holland rejected in 2005.

The provision of the Lisbon Treaty that "The Union shall replace and succeed the European Community" (Art.1.3, amended TEU) makes absolutely clear that the post-Lisbon Union will be quite a new entity, as the European Community of which our countries are all currently members ceases to exist.