It still seems to me that the French system has better assurance of making a good Earth contact and is probably cheaper to manufacture.
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Add to that the fact that the French system only allows the plug to be inserted one way and so allows for polarization and in my view it is far superior.
First, the "French" (those sockets are also used in Czech Republic, Slovakia, Poland, Hungary and elsewhere, it is not a France-specific design) can and do suffer from the same kind of wear as the the regular German Schuko. Just the problem often happens on the plug side - if the contacts are worn and loose you will have a poor connection, esp. when people yank the plugs out of the outlets by the cable.
These sockets are also specifically to be always considered as
not polarized, regardless of whether or not you can insert them only in one way. If you assume you have always live on the left and neutral on the right (with the earth pin at the top), sooner or later you will get shocked because there are many installations that don't follow this rule. There are also the T-splitters that reverse the polarity on one side - and they are completely legal and common in France and elsewhere. One has to always consider both wires as live and at a dangerous potential to earth. Never ever assume that the European mains plugs are polarized or you will get a bad surprise at some point.
The German Schuko design took this to the logical conclusion - nothing should ever rely on the polarity of the plug (e.g. switches in order to switch live and not neutral) - and made the plugs fit in either way. Which is often an advantage, esp. when trying to fit 90deg plugs into a poorly placed outlet.
In addition, there are plenty of installations that either have the earth pin not connected at all or (worse) tied to the neutral inside the outlet. So