Which Canadian city would you choose?

Montreal or Quebec City, but check historical weather stats. (Meaning I wouldn't do it at that time of year.)

Montreal or Quebec City are great. Consider visiting both if you have a week.

Montreal is more expensive. You can do QC in a couple of days.

No contest - Quebec -one of the prettiest cities in North America.

Quebec City would be our first choice, but if you can add a couple of days, doing it and Montreal can be done.
As someone mentioned, check the weather as it might be a bit iffy that time of year.

Québec & Montréal

International air service to Quebec City is limited. Air/train connections between Montreal and QC are more plentiful. It would be ideal to do a multi-city flight route to Montreal and Quebec, but you will still shortchange your stay in those cities. More efficient, in my view, to stick to Quebec City and find an organized day trip to see some of the countryside.
PS: "Early" spring in QC may not be as early as you expect in your home town.

Not quite early spring, but Carnaval de Québec (February 2-11, 2024) is lots of fun as long as you dress for it. The Québécois really know how to do winter right.

Wonderful.responses and we have now decided on Quebec. Thanks for your help.

Agree with the Quebec City and Montreal recommendations and also suggest Ottawa and its unique blend of French and English.

Wow another idea never thought of Ottawa thanks

Old town Quebec City is so French, when I was there, they were filming a World War II movie on the square, complete with German soldiers, and people waving baguettes.

You mentioned that you have mobility issues in one of your other posts. For info, Quebec is divided into an Upper and Lower town - connected by a long stairway that tops out near the Fairmont Chateau Frontenac hotel (very nice indeed). There's also A Funicular
that makes it pretty easy to get between the two tiers. Once on one level or the other the walking is pretty level, though things can get a little congested at certain times of the day in some of the narrow pedestrian lanes, especially if there's a cruise ship docked near the lower town.
You can get a preview of what the various little streets look like by using the Street View feature on Google maps.

What is your time constraint?

If you do have 4 full days, I suggest spending all of it in Quebec City, all the more so, if your desire is to immerse yourself in French language and culture. In North America I find Quebec the most intriguing, fascinating, and lovely place to go, ie, plainly put, my favourite place. I went there in the summer of 2017 for 5 days, walked all over the old city.

No time constraints just financial right now as just did three weeks in Europe and have three big trips in 2024 so really don't want more than five days max on this one. Thanks for your help.

I would say Montreal, gives a perfect 'French' getaway.

Early spring (April) in Montreal and Quebec City is not warm - check the weather and pack appropriately . Montreal is a wonderful city and there is lots to see and do. I haven't been to QC yet - it's on my list - I've heard it's lovely too but the main sites can be seen in a few days.

I think Quebec City is doable with mobility issues. I did it with a not-quite-three-year-old mostly in a stroller. The funicular ran frequently and was pretty convenient. If you stay in the old city, most of your sites are close-by and it's easy to return the hotel for a rest (the toddler kept regular nap-time in Quebec). There are some more distant sites you'll probably want to go to; taxis will easily get you there and back (we left an adult with the sleeping toddler and did that).