I have been on work contracts to Paris twice, and both times I have had accommodations at Citadines St Germain. Understand that I could never afford to stay here in my real life. That being said....
Firstly, you should fully consider the location... Located on the Left Bank, in the heart of Paris, Citadines SGP is ideally situated between Notre Dame and the Louvre. It is only two blocks from Place St. Michel (and RER/B or various metro connections). One can not find a better location to see most of the essential Paris sites by foot or public transport. The location provides easy access to the following by foot: The Rodin Garden/Museum, Luxomburg Gardens, The Latin Quarter, St. Germain Des Pres (area), Pont Neuf, The Louvre, Tuileries and the shopping of Les Halles...restaurants and shopping also abound.
Called "Apart-Hotel" the rooms consist of a bedroom, separate lounge, toilet, kitchen (two burner cook top, fridge, mircowave/covection unit, stocked with kitchen utensils) and separate bathroom. Most rooms have a couch which is actually a trundle bed and VERY comfortable.
The views from the rooms on the back side of the building (rooms ending in the 02-11 area) have some of the most spectacular views you can imagine in Paris. You gaze out your window as the sun sets against the backdrop of the Eiffel Tower. Rooms on the opposite side of the building face Notre Dame/Seine. Certain rooms also have balconies.
The staff is friendly, professional, and eager to help. All are multi-lingual (You may easily be served in French, English, and Spanish). Certain employees also speak: Arabic, Italian, and Vietnamese.
Breakfast is 14 Euro, but should be considered as much better fare than your standard continental breakfast. Fresh French bread (with various accouterments), hard/soft boiled eggs, country ham slices, cereals, waffles, cheeses, juice, make up a splendid start to your day, should you so choose.
Daily and weekly cleaning service is offered (additional fees apply). Guests also have access to laundry facilities (5euro for wash cycle and 4 euro per drying cycle).
The price is not cheap: at 210 Euro per night, most would not consider this for their typical vacation stay. However...Should this price fall within either your personal budget, or your business expense report guidelines, I highly recommend a stay here. They have made me feel like it is my home away from home. They are quick to offer guidance when needed, and privacy when required.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC