I was refused visa from france embassy, when can i reapply again?

I was refused visa from france embassy, when can i reapply again? I have been having visas from the france embassy for long and my last visa was a year visa that got expired, i went to renew my visa and they refused my visa for the reason of says , ----The information provided to justify the purpose and conditions of the proposed stay is not reliable. i was refused on the 30th of July 2011, when can i reapply for another visa? Thanks for your help all the time