I'm afraid I have to agree with other reviewers of this Blu Ray version of William Friedkin's masterpiece. It looks awful a large part of the time, which completely ruins the other times when it shines.
Ironically, the problem lies in the film's strength - its gritty portrayal of New York and the drug culture taking a grip of it in the early Seventies. The Director wanted realism - not just in his actor's performances, but literally how their New York playground looked - so he went for that. Movements are blurry, alleyways are hazy, characters are observed from an out-of-focus distance (aping what Popeye Doyle sees) - everything's grimy and washed out - matching the film's down and dirty feel.
Unfortunately when you get outside of the sunny Marseilles sequences and into the seedy bars and restaurants of the Big Apple - the Blu Ray picture resembles worn out videotape - it's really awful. Which is such a shame, because as you watch it again - but this time on the big screen - you realize what a blindingly fabulous film "The French Connection" is - and how it deserved so much better than this (the superb sequel is squeaky clean on Blu Ray - a joy to look at).
In fairness to Fox, the opening credits are squeaky clean - no lines, no scuffs, nothing - no print remains that clean after 38 years, so some restoration has to have been done - unfortunately when you get to the street action - instead of enhancing the watch - the Blu Ray only makes the deliberately grainy effect look even worse.
Half way through it - I couldn't stand to look at it anymore - I turned it off...
Unless you absolutely must own this, rent it first before wasting your hard-earned on yet another dog on this increasingly frustrating format...
What a disappointment.