I will be traveling from Washington, DC to Prague via Air France with hopefully just carryon luggage. The Air France website gives specific dimensions for the perimeter of the carry on luggage allowed. My suitcase exceeds 2 of the 3 dimensions by a couple of centimeters. Do they enforce these dimensions, or if I am reasonably close should I be able to get by? Thank you.

It all depends on how full the plane is and how strict the particular gate gents are. In Europe I've seen a lot of people have to gate-check carry-ons that were over the size just because of the wheels (you have to include the wheels when mesuring) when the plane was full.

I would also check the wieght complies with their terms of carraige.
You might get away with a few centimeters but don't bank on it.

The sizers that they use at European airports are not the slightest bit forgiving. As a guess, I suspect you might get your carry-on on board in Washington, but I'd be rather less confident about any remaining flights.

Since they are soon going to be charging for an extra checked bag I would expect, and hope, that they are also clamping down on carry-on bags on transatlantic flights.
I would not rely on goodwill from the airline.

Air France have been known to be very strict on carry-on dimensions, especially on inter Europe flights. Often they will test the bag as you enter the aircraft and will put it to be checked if they are unhappy with it. A couple of centimetres is nearly an inch which could be the difference between it being acceptable or not.

Be prepared for your carry-on to be checked - ie don't put anything in there of value and keep essentials for the flight on your person. That way if it is checked it isn't a disaster.

My experience is that on international flights, AF is fanatic about weight for carryons, less about a few centimetres, but your mileage may vary.

I flew AF through CDG last week and they were having people put carryons in the sizers. A couple near me had rolling back packs that didn't look large to me but they said it was a very tight fit and it usually is not.

So, as someone else advised don't have anything in the carryon that you'll need on the flight.

I flew Delta operated by Air France to Budapest, via CDG, last fall. My carry-on was a soft-sided rolling duffle that matched my checked bag and that I had used for multiple other trips to Europe, and it did fit within the size requirements. I had, however, for convenience, put my full length coat inside as well as my small travel pillow, thus making it rather "puffy." While he didn't measure my bag or put it in a sizer, the gate agent at CDG looked at it and said I would have to check it. I took my coat and pillow out, and after un ou deux "s'il vous plaits," he then said it was okay. My flight home was Delta operated by Czech Air from Prague, and I had no problems.

For my trip to Greece last month I bought a digital luggage scale from Magellan's and new "featherweight" luggage, including a slightly smaller wheeled carry-on bag, just to prevent any future issues. After arriving in Athens, I had a brief layover before a flight Thessaloniki on Olympic Air, whose requirements are more stringent. However, no one even glanced at my bag.

<i>My experience is that on international flights, AF is fanatic about weight for carryons, less about a few centimetres, but your mileage may vary.</i>

This is my experience, as well. In my experience, using a wheeled carry-on is a dead giveaway and they will weigh it, and it will usually be over the limit.

They are also strict about the number of carry-ons.

Those people flying with Easyjet (a lowcost European airline) your carry on luggage can be of any weight (within reason - i.e. you have to be able to lift it into the overhead lockers)though size does matter...

My experience is also that they are pretty strict, although almost every flight I've had on them in the last decade has been virtually full.

A Delta flight operated by Air France IS an Air France flight, not Delta. You can just buy your ticket through Deltaon a codeshare.