Abstract: The European Parliament has seen a constant development of their competences, but he did not get the right to fix its own seat. This issue is due to a long conflict between a few countries (notably France) and MPs.The changes introduced by the Lisbon Treaty on the composition of the Assembly are the source of another controversy. At first glance, the principle of digressive proportionality favors small states, but the comparative reduction of parliamentary seats for the big States should be assessed in conjunction with the new method of calculating the qualified majority in the Council European Union, to fully benefit most populous states. The result is that the influence of small states on the decision of the Union decreases.The European Parliament's political groups are centers of power. These groups should be formed on the basis of political affinities, which excludes the association of members who have incompatible ideologies. Recent changes in the conditions required for the formation of a parliamentary group are conducive to large groups. If we look at the relations between European political parties and European parliamentary groups, we find that, for the moment, the European political parties are weak, the real impact is at the European Parliament's political groups.

Keywords: European Parlament, competences, small states.