Italy and France are fighting at the moment a battle on Suez, a French company that Enel (an italian company) is trying to buy. In order to prevent that, the French government agreed on a fusion between Gaz de France and Suez.
Beyond the legal (tricky) problem, there is a much bigger question. Why should a European state do everything to keep a company national? The short answer is quite easy: to protect national interest.
Unfortunately, the short answer clash irremediably with the european ideal of the single market and with the creation of the euro in order to further that single market.
The reason for such a behaviour can be found in France's present political situation. Hurt by the defeat in the referendum, France is now a wounded animal, without clear guidance (Chirac, its president, is over), and more importantly, without clear ideals. France gave up its role as a committed european country and is now looking for its own identity, poor little one.
All this is bad in the short term. It is awful to see national protectionism re-emerge. But in the long run, it is clear that such an attitude would not be viable.
Europe will emerge from the slow death of nationalisms, even though that slow death is at times producing consequences hard to digest. This is particularly regrettable at this very moment, as Europe shows its weaknesses to the whole world without shame, but the only way forward, and away from this mess, is union, not egoism.