24 hours in Paris

Are you flying in? Paris is quite a detour from any route between Dublin and London.

Find a hotel as centrally located as you can, I'd suggest near Place St-Michel where you can easily walk to many places and have good Metro connections. Booking.com is a good search tool with useful filters and reviews by people who have actually stayed there, but make your actual booking through the hotel's website.

Here are our host's ideas for what to see with varying amounts of time in Paris. His one-day plan makes sense to me. If you're staying near St-Michel you can do it all on foot except the evening stop at Trocadero which requires the Metro. But your own interests may differ.

The fastest and easiest way to get from Paris to London is the Eurostar train. Get your ticket right away as prices will rise.

What is your dream of Paris? Do that. With so little time, rather than cramming tons of stuff in and being hassled, pick two things you really want to see and do and then have a few secondary things if there is time. A lot to be said for walking around the center, sitting and enjoying coffee with a good view. Be sure that some of this includes a stroll around Notre Dame at night -- unforgettable and perhaps also a view of the Eiffel Tower after dark from Trocadero.

Get a hotel near Notre Dame the center of Paris. Our go to is Henri IV Rive Gauche but there are many. You can hop on the train in the morning to CDG for your onward flight (or take a cab to Orly if flying out of Orly)

I would try to stay as close to the things you want to see as possible. Near Notre Dame is a good option.
We stayed here about 5 years ago and would recommend it: https://henri-paris-hotel.com/en/hotel.html
We were able to walk to most places or hop on the metro. If I only had one day I would go to Notre Dame for sure, maybe the Musee d'Orsay if the weather wasn't great. If it is beautiful spring day I would wander through the Luxembourg gardens, the Marais area, walk around the Eiffel tower or Sacre-Coeur.
I would also suggest a boat trip in the evening -if you time it right you see the city at sunset and the lights come on the Eiffel Tower.
I would skip the Louvre, arc de Triomphe, etc....for this trip.
I would try and see 2 or 3 major things at most and then just walk around the city if you can-check out cafes. Then you will know what areas you want to see when you go back on a longer trip.

"....... a quick stop in Paris between Dublin and London."

Not understanding. Do you mean you would fly to Paris from Dublin and then take the Eurostar from Paris to London?

Hotel Muguet in the 7th.

See the Tour Effiel and surrounding park. Rodin and Monet Museums. Walk along the Siene. Fat Tire bike tour.

Dinner at Aux Bons Crus in the 11th arrondisment or Cafe de la Nouvelle Mairie in the 4th.

Take the Eurostar to London early the next morning.

First, assume you’ll be back to give Paris it’s fair shake. I almost guarantee you will. Do not go into any sights, it takes too much time. Just enjoy the city itself. Stroll around Isle de la Cite, and along the Seine in that area and look at Notre Dame (the outside). Walk along the Seine past the Louvre, through Tuileries garden to Place de la Concorde. Hop on the Metro to Arc de Triomphe (straight shot) and see the Arc. Same Metro back to Trocadero, see the Eiffel Tower from there, then walk to it and under it. Hop on a river cruise boat back to Notre Dame, have dinner. Walk around some more at night. Go to bed happy and tired. I would do that day in Paris in a second.

Note: If it’s spring/summer and the weather is nice and time depending, Luxembourg garden. Palais Royal garden is also a nice stop and is right behind the Louvre. Great RS recommded cafe right by the entrance there.

Honestly, not a good use of your time or money.

If, as you say, you have just 24 hours, that means you will end up spending almost all of those hours arriving, getting in to the city from the airport, getting settled in your accommodations, sleeping, eating, attending to personal needs/tasks, checking out, getting back to the airport, going through security, etc. Even if you skip the airport for a second time and take the train to London, you will only end up with a few (literally, like maybe 2 or 3) usable hours when you are not spending your time taking care of basic human needs.

Sure, having 2 or 3 hours in Paris is better than having none at all, but consider what you are actually trading away to get that: a whole day elsewhere on your trip (presumably in Ireland or the UK). While it sounds romantic and lovely to blow through Paris on your way, what you're really doing is adding another travel day to your trip between Dublin and London, and that comes out of time spent elsewhere.

If you already have too many days in Europe and you're looking to just burn one, OK, but IME most folks visiting Europe have way too few days, and spending one more "in transit" day just shortchanges you further. If it were me, I'd try to undo this, and spend that extra day in either Ireland or the UK.

Sorry, I'm sure that's not what you want to hear, but gotta be honest, the only way I see this making sense is if your trip to Ireland/UK is "too long" and you've run out of good things to see and do there (which seems unlikely to me).

You have left out some really critical information: How long is your trip - how much time do you have in Ireland and the UK, and where are you planning to spend it?

Would you really consider spending a day in Atlanta, in between going from Dallas to New Orleans? Or a day in Chicago on your way from DC to New York city?

Thanks for all the advice!! Ended up deciding it wouldn't be worthwhile so we're spending another day in London!