The lack of time or money does not mean you'll have to reject a treat to travel! One can organize a trip in an economic way which soonheless will not spoil the general effect. Here are some hints at how one can do it.
First of all download all the necessary information (eg maps of Paris, museum info, information about monuments and hotels in Paris etc). Book a hotel. Bear in mind that the closer to the center the more expensive the hotels are. Learn some French words and probably buy a guide book. The majority of Frenchmen does not know foreign languages. You'll have a hard time trying to ask something, so the guide book will be of great value. Buy the tickets (by Air France for instance) – and fly straight to Paris!
In Charles de Gaulle Airport get some cash and take a cab or RER to hotel. I advise you to buy a Paris Visite Pass if you will use RER / and (or) the Metro. An absolute must is a purchase of a 3-Day Carte Musee. That is a museum pass that will help you avoid long queues. It pays for itself after about three visits to monuments or museums.
After checking in a hotel you are free to visit any Parisian sightseeing. The absolute must-sees are: Notre Dame, St. Denis, Sacre Couer, Arc de Triomph, Musee d'Orsay, Versailles, the metro, Rodin Museum, Center Pompidou, Place de la Concorde, Les Arenes, a bateaux mouche down the Seine, the Opera, the Eiffel Tower, Champs de Mars and les Invalides.
You can have a tasty but not expensive dinner in one of the many restaurants in St Michel district near Notre Dame. Greek or Middle Eastern are the pretty cool. Anywhere the cafeterias are not bad either.
Think over your adventures beforehand. You'll spare your time and money then. I can advise you to book the excursion "Bateau Mouche" – that is a river stroll on a glass top boat.
Paris is wonderful. You do not need to go on many excursions. Just walk along the Parisian streets to feel the romantic atmosphere of the French capital!
So as you can see from the written above the main rules of economy are the following: think trough everything beforehand. Find the necessary information. Book what is possible in advance.
I'm sure that following these rules you will save your money, time and nerves! 😉 Enjoy your trip to the romantic city of Paris!