From Dublin I would say No. Yes it's doable but half the time you'll be travelling to/from the airport/on a plane. Maybe spend a night and get at least a full day in.
To do what in these cities?
I'd want to be at any airport 2 hours before a flight, as I'm a cautious traveller. So I probably wouldn't do this myself. It would be a very packed day, and my personal view is that London and Paris deserve more than a day trip.
Only you can decide if it's worth your time. I'm sure that others will point out the advantges they see in taking a day trip to London or Paris. I can't see many myself.
Fly from Dublin to London City airport as you would have more time then to spend "being a tourist". you could get an early flight with City jet, and 1/2 an hour after you land, you could be at the Tower of London
First flight out is to CDG @ around 6.00, last return flight just before 22.00. While that looks promising, it takes around 2 hours to and from airport to city centre, so that does not leave time to see very much. Would consider an overnight trip for this.
We are traveling to see our son who is studying abroad for the semester in Dublin
Was going to do a day trip to Cliffs of moor but read reviews that November the weather isn't always cooperating and would not want to take that long day trip if once we get there it's too windy or foggy and it is closed off.. can you recommend other tours that are must see? Thanks!