If you're thinking of a trip to Paris and want to find rock-bottom prices on air, lodging, and food, here are some tips to keep in mind. The cheapest airfare this writer could find is $369 round-trip charter from New York, through a travel agency called Nouvelles Fronti`eres (212) 764-6494. This flight leaves only once a week, on Saturdays. There is no refund if you choose to cancel less than 30 days before departure, although changes are possible with one week's notice and a penalty of $40. A Nouvelles Fronti`eres spokesman says they've never had to cancel a flight.
Air France's subsidiary, Air Charter, flies from New York and Boston to Orly Airport near Paris (and also from New York to Nice). The New York-Paris fare on Tuesdays is $209 one way. The rate goes up in August to $279, then back to $209 in September.
From Boston, Air Charter has Sunday departures between June 23 and Sept. 15 for $239 one way, except for a few departures at the beginning and end of July and of August, when the price is $269 one way. Air Charter uses Air France 747s and crews.
Air France, TWA, and Pan Am are the three main carriers to Paris. They all have packages and tours. New on the scene are Delta, flying from Atlanta, and American from Dallas. Accommodations
Several small hotels in the heart of Paris are clean, convenient, and modestly priced.
One that is highly recommended: The Hotel des Deux Continents, 25 rue Jacob, in the St. Germain quartier. Described as ``nice and simple and inexpensive,'' it has rates from 217 to 264 francs ($23.90 to $27.85) per room, single or double occupancy, including breakfast.
Another is the Esmeralda, 4 rue St. Julien le Pauvre in the fifth arrondissement (or section), where singles cost 58 to 146 francs ($6.10 to $15.40) and doubles 198 to 350 francs ($20.90 to $36.90).
The Grands Hommes Pantheon, 17 Place du Pantheon, charges about 460 francs ($48.53) for single or double occupancy. Food
A good guide to caf'es and restaurants is Patricia Wells's ``The Food Lover's Guide to Paris'' (Workman, New York). It tells you where to go and what to order -- it makes you hungry just to read it.