Was France ineffective at censoring books, or too effective? One could argue either way.
On the one hand, France had a booming black market. That means, if nothing else, something that people wanted was illegal and hard to get. If getting the products were easy, the market wouldn't be booming: people would just go and get their own, cutting out the expensive middleman. If the products were legal, there would not be a black market for the product in the first place. If the product are illegal and hard to get a hold of, it often means that the body that declared the product illegal is doing a pretty good job keeping the product out of the area. France had a booming black market in illegal books, so it is reasonable to think that France was doing such an effective job at censoring books to make this market necessary.
On the other hand, the uncensored books were still making their way into France: this, by definition of 'to censor', the censor was ineffective. To censor, according to wikipedia, is to suppress communication which may be considered objectionable. According to Miriam Webster's Online Dictionary, however, it is to examine in order to suppress anything considered objectionable. The Free Online Dictionary and Dictionary.com agree with the Miriam definition. I make this distinction for the simple reason that the slight difference between the two given definitions makes a difference in the argument whether or not France was effective in their censoring. France succeeded in it's fight to suppress objectionable information: if the product was not suppressed, in this case made illegal, it would not have become a black market. At the same time, France failed in it's attempts to examine most of what passed through the black market: it was hardly likely a shady merchant would take all his wares to the nearest censor and ask him if everything checked out.
I generally believe that France was too effective at censoring which lead to it's inability to censor: if a spring is wound too tight, it will become useless. Likewise, if the censoring becomes too good, ways will be devised to make it less good. I would be curious to learn more about how France censured it's books and how it's black market worked.
