Jerricho It wasn't
just the French; the UK, W. Germany, Ireland and the Dutch originally refused to delegate airspace to Eurocontrol.
Maastricht UAC originally controlled only the Upper airspace of Belgium and Luxembourg FL195+
In 1974 The Hannover airspace FL245+ was added with Lippe Radar (German Air Force) also moving there. Additionally Eurocontrol Centres were built at Karlsruhe and Shannon and were both rapidly re-nationalised.
In 1987, after considerable political infighting, the Dutch airspace FL300+ was added.
The division level is now a uniform FL 245 and sector boundaries do not neccessarily conform to national boundaries.
The latest move is to separate the UAC from the rest of the organisation and to nationalise it, probably under the DFS (Deutsche Flugsicherung)
The treality of the One Sky movement, which, by the way, is not new, having been around for some 10 years, lies not so much in consolidation of the number of centres, however desireable that may be, but in the adoption of common systems
* and procedures.
Findo I think has hit the nail on the head, in fact let's take it one step further and allow controllers to work from home. The technology exists
The introduction of the "Free Skies" in a couple of years makes this more and more imperative; although the ideal of smaller, or less efficient, centres being consoldated across national boundaries is probably still as far away as it was when I joined Eurocontrol in 1970.
Lon More
Here before Pontius was a Pilot or Mortus was a Rigger
* Much of the development work required for NERC duplicated that already done in Bretigny sur Orge under the auspices of Eurocontrol and was therefore readily available. Little use seems to have been made of this.