Ireland, though part of Europe, is an island. So although you can fly into Dublin, in order to get to Paris you will have to either get a flight or a boat to get to the continent of Europe. You can travel from Dublin by train to Rosslare in the south east of Ireland and get a ferry to Cherbourg. Or to Cork in the mid-west to Roscoff. Once in France you can then connect into the French train network (SNCF) to travel to Paris. I hope this helps.