Written in 1944, there is a specific passage where he argues against this "but I have nothing to hide!" argument, only criminals benefits from hiding, right ? He talks about how a simple citizen who never had trouble with the law should stay perfectly free to conceal his identity whenever he likes for whatever reason, and laments how this very idea already died.
The extract is available online [1] in French, the google translation [2] is not that good.
[1] http://www.books.fr/quand-bernanos-predisait-une-societe-sou... [2] https://translate.google.com/translate?hl=en&sl=auto&tl=en&u...