Prison sentences for those who deny the Holocaust of 1939-45 or Armenian genocide, 1915-17, are among the worst imaginable ways to "combat racism and xenophobia," their supposed purpose. For one thing, such laws probably won't work where they are proposed--they go against hard-won conquests of free speech in western Europe, as well as the commercial interests of a lot of mass media delighted to stir up a storm about anything. But the greater threat is that they might work, at least somewhat, not to make people feel more tolerant toward other races, but to shut up about their unofficial, unsanctioned opinions. And then where will we be? In something like Putin's Russia, where only the official story gets expressed, or maybe Iran, with its deep and complex apparatus for control of opinion.
Curiously, last year the then-leading candidate for president of that country (he lost, though) argued that censorship wasn't working. The man who did win, Ahmadinejad, has not dismantled the censorship apparatus, but has come up with imaginative ways to test the West's tolerance for dissent: a cartoon contest lampooning the Israels leaders' supposed Holocaust-complex.
History should be left to the historians, to debate and argue out their interpretations. The evidence for the so-called "Holocaust" (the real event, or series of events, was far worse than any real holocaust) is overwhelming, it appears to me and should appear to most people. So those who claim it didn't happen can be refuted by evidence. Denying those "deniers" a voice is denying ourselves a chance to debate and clarify many details of a very complex history, in which vast parts of European society--not only in Germany--were complicit. As for the Armenians, the debate is not over whether tens of thousands or more died, but over whether (a) their death was deliberate policy by the Ottoman leadership and if so, (b) what responsibility modern Turkey, the secular nation-state created by Attaturk, has for its imperial predecessors. We should do everything we can to get Turkey to acknowledge the issue and join an open search for the historical truth; punishing in France those who denied that it happened is as obnoxious to free speech as punishing in Turkey those who argue that it did.
BBC NEWS | Europe | Push for EU Holocaust denial ban
See also The fight against Holocaust denial by Raffi Berg (BBC)
But most of all, see Index on Censorship