Is an hour enough time for an international flight connection through Paris CDG?

Rebook.

Rebook. Rebook. Rebook.

From my own experience in Paris

• You're going to be hauling ass & knocking old ladies out of the way to physically get from one end of the airport to the other. There is no tram or tain or bus. There's shanks mare (i.e. your own two feet).
• You'll be in the immigration line with the entire contents of your plane (and possibly multiple others. I have been in the immigration line (the very long, long line) when one of the only two immigration officers on duty went "Oh look, 3 wide-bodies just came in from across the Atlantic. Time for lunch!" And left. The French have a different attitude. Your hurry is not their hurry.
• And that all assumes your flight will land on time. In case you haven't been watching the news lately, I wouldn't count on it.

Personally, I would want a minimum of 2h in Paris & ideally 3. You think that's a long time to hang out in an airport. Wait until you run across Charles de Gaulle to the far end of the terminal only to find that your flight - which is nearly done boarding - has been moved to the other end of the 1/2-mile terminal.

Rebook.

If the airline sold you this connection as a single ticket, they are rather confident you will make it.

It you don’t, they have to rebook you on the next available flight, and if that flight is the next day (unlikely in your case), they have to book and pay for an hotel for you. In some cases (not this one), they would also have to pay compensation for the delay. So they have a strong incentive to only sell connections that are actually doable and to make sure you can do it in time.

However, there are quite a few factors which may affect whether you’ll actually make it or not:

• whether the incoming flight is on time. Today’s DL98 is several hours late, for instance.
• Which gate you arrive at. Terminal 2E has 3 concourses (K, L and M gates), 2 of which (L and M) require you to use a people mover to get to the main building where you’ll go through passport control. But L gates have a shortcut to 2F where your onward flights departs. Hopefully you won’t have to use a bus to get to the terminal.
• How long it takes you do deplane. There’s quite a difference between being the first to deplane (flying business) and the last one (in the last row of economy). Make sure you book a seat towards the front.
• How fast you walk and whether you are “encumbered”. It takes a lot longer to navigate through an airport if you have 3 small children in tow.
• Whether you have status. If you are an elite member of the frequent flyer program of any of the Skyteam airlines, or if you travel business or first (possibly also premium economy, I’m not sure), you get “Sky Priority” which in CDG translates to the purple “Accès N°1” lanes and gives you priority at passport control and security.
• Whether you have an EU/EEA passport or not. Lines at passport control for EU/EEA passengers are usually quicker than the others.
• And the biggest unknown: how long will the queues be at passport control and security.

With a flight on time and status, for a well-travelled passenger this is unlikely to be a problem at all. For most other situations it should not be a problem, but as you see there are quite a few variables.

Note that if the airlines feel the connection is tight (they probably won’t unless the flight is a bit late, but not too much), you are likely to have staff at the gate to assist you and get you through the lines quicker. But the rules for when they do that are a mystery.

If your flight is a bit late, make sure you let the crew on board know, they may be able to get you off the plane quicker or get you other forms of assistance.

Be prepared: check out the maps of the relevant terminals in advance so you know what you should do based on the arrival gate, check the status and gate of your onward flight, have your documents ready.

Also check for alternate flights in advance, so in case you don’t make the connection and they need to rebook you, you know what the choices are.

Technically, because the itinerary was sold as a single ticket, then they should not go below the minimum connection times that the airport requires, but that doesn't mean its necessarily enough.

From various sources cobbled together, it looks like for international to domestic at either of Charles De Gualle airport or Orly airport the minimum recommended connection time is 60 minutes.

But what does that mean?

Well, all it means is "how much reasonable time do you need to deplane, go through whatever customs or immigration checks you need to do (as you will be going from international to Schengen, you will pass through immigration and customs), get from one place to another in the terminals and be ready to board your second flight".

What it does NOT cover is "what happens if my inbound flight is delayed?"

So, a 60 minute connection time is cutting it very very fine IMHO. If your flight from DTW is delayed, you almost certainly won't make the flight to Rome. If you are a slow walker, you almost certainly won't make your flight to Rome. If immigration is busy or you have a problem there, you almost certainly won't make the flight to Rome. And so on.

You would probably find the airline helpful to rebook your Rome flight should any of the above events transpire, but why risk it? You might not get another flight for hours or until the next day.