Almost immediately after the accident at Fukushima Daiichi, Chancellor Andrea Merkel announced a temporary shutdown of Germany's oldest nuclear plants. Counting one plant that had been shut down prior to the accident, the sixth of seven plants was shut down on Friday. The Chancellor was accused by some of playing politics in making the decision, as there are elections coming soon in several Länder. The current CDU-CSU-FDP government has previously stated support for keeping the currently operating reactors open longer, which is unpopular, and a reversal from the policy of phase-out that had previously been in place.
relative geological stability of the region compared to Japan. The seven plants represent about 8% of Germany's total nameplate electricity generation capacity, so there is the potential for shortages. Only two plants with a total of two reactors are located on the coast: Brunsbüttel, which was already shut down, and Unterweser. The first is a boiling water reactor built by KWU, and from what I can gather, it has a design similar to a General Electric BWR/3 with Mark-1 containment. The other is a pressurized water reactor derived from a Westinghouse design. Of the other five reactors, two more are BWRs of the same design as Brunsbüttel, including one that has been in long-term shutdown due to technical and safety problems. The rest are PWRs similar to Unterweser. They are all located inland on rivers. Like all other coastlines, there is some risk of tsunamis on the shores of the North Sea. But without a subduction zone nearby, massive coast flooding would only come from underwater landslides.
gas-cooled reactors, France switched decisively in the late 1960s to PWRs derived from Westinghouse designs, and built large plants with up to six reactors of the same design. Germany built both BWRs and PWRs, and even mixed the types at two plants. However, only in the former East Germany was a plant with more than two identical reactors built. Germany experimented with more unconventional reactors types than France, though none of the plants were all that successful, and all have been shut down. France put a lot of effort into sodium-cooled fast reactors, but the first and only commercial-scale plant of that type was a failure. France only operates PWRs at this time.
The mostly likely explanation for the contrast between the two nuclear programs is the nature of the two countries' constitutions. France is a unitary state, which means local and regional governments only have powers that are granted by the central government. Germany is a federal state, and each Länder has the right to administer certain functions. France has had one monopoly power generation company since 1946, whereas Germany currently has several companies. (I have no insight into the history of the German power industry.) I think the scale and centralization of EDF, combined with the French love for grand projects like the TGV, has lead to the dominant role of nuclear power in the country. France also has two geographic advantages over Germany: it is much less densely populated, and it has a much longer coastline. That certainly allowed greater flexibility for siting plants. France was also never on the front line of the Cold War, so the prospect of war-damaged reactor was less likely (though I have no idea if the issue entered the minds of decision-makers in either country).
At first glance, nuclear power clearly "works" much better in France than in Germany. But entirely left out of this discussion so far is the issue of pollution. I have no idea how much nuclear waste exists in each country, how much has leaked into the environment, how well the high level waste is guarded, or anything else along those lines. Without analyzing that part of the nuclear complex, no evaluation can be complete. France has also been "lucky" in one regard, which is that the design it adopted appears to be safe at this point. No doubt a lot of study went into the issue before the choice was made, but that was done in the 1960s, when the industry was only 10-20 years old. The depth of knowledge was much, much less back then, and a wrong choice or a bad design could have ended up crippling the country if dozens of reactors had to be shut down at the same time.
Added 2011/03/22: Here's an interview with the head of E.on, Germany's largest electric utility, talking about the problems the shutdown may create in the Germany grid. Of course, it's quite possible that he's exaggerating or even lying to boost his company's fortunes.
Added 2011/03/27: Former Chancellor Helmut Kohl lays into Merkel a bit.