This isn't a trip report? You might want to have that tag removed becaus someone who may be able to help, might not want to be bothered reading what they assume to be a report.

I cannot imagine what you are basing these fears on. Many people enjoy (and some prefer) travelling alone. Lonely is a state of mind.

I don't think you're planning the trip with the best attitude - that you'll be lonely and bored. I can't imagine being bored in Paris. Perhaps you should postpone your trip.

I really don't know what type of tips you're looking for but stay in hostels and meet other people traveling on their own.

There is no way that you can be bored, and you will only be lonely if you want to be. While it is not always easy to meet Parisians on a short trip, it is VERY easy to meet other tourists with similar interests who are looking for someone else with whom to visit places.

For various reasons, I generally travel alone. If you are comfortable being alone in your home country, I think you'll be equally comfortable in Paris or wherever else you go.

I think you need to plan carefully, using a guidebook or guidebooks, so that you know what you want to see and do. Don't worry about making mistakes. Sometimes mistakes lead to the greatest adventures.

If you're not comfortable being alone all the time, take a day tour or two.

I know this isn't the answer for everyone, but I have a little digital recorder that I bring when I travel. If I see something I'd like to comment on, I just tell my little recorder. When I get back home I can listen to it and relive my experiences.

Paris is never boring when you're a solo traveler. On the other hand, friendships have ended because of traveling together. I say you're in the better position.

I know you are disappointed but you will be OK. No need to feel lonely,, unless you choose to. Alone is not necessarily lonely. Paris is a wonderful city alone or not. Enjoy the time, experience the city, the food, the art, the culture, the fashion, the pain au chocolat....

One nice thing is you can do whatever you want, when you want to...no one else's schedule comes into play.

Not sure of your interests, but climb the Towers of Notre Dame to get a great view of Paris and see the gargoyles up close. visit Ste Chapelle ona sunny day, if possible. take an evening Seine cruise to see the monuments all lit up. Visit the Musee Rodin, l'Orangerie and D'Orsay for spectacular art. Take the Metro out to St Denis, the burial place of French kings.

Into Champagne? Take the TGV to Reims and visit the majestic cathedral where French kings were crwoned....visit one of the Champagne houses.

If it is still in October, take the train to Vernon to see Giverny, Monet's gardens.

Ever heard of Versailles? Get on the RER and go see the spectacular Hall of Mirrors and the Petit Trianon.

You will have no time to feel lonely!

My sister will be traveling to Paris alone too this October! At first, she was hesitant but I seem to have convinced her she will have a blast. Paris is the perfect city to be with someone or to be absolutely alone! There's so much to see and do you won't even notice being alone. Have fun!

Correct me if I'm wrong, but where you are going really has nothing to do with your question. I'm assuming you are in the USA? My question would be, would you be bored touring a city in your own country solo?
If the answer is yes, then all you need to realize is if you put a little effort into your planning , you can have a very enjoyable time on your own in Paris!

I fear your low expectations will be a self fulfilling prophecy. Either get your energy up and plan a great trip or don't go.

Two issues, bored and alone.

Resolving the alone bit, you need to connect to people who have similar interests so chose from one of (do a language or art course, pop into a religious centre of your own choice, stay in a people friendly accomodation like a hostel rather than a hotel)
Resolving the bored bit, what do you like to do? Art, eat, drink, party, bike riding, horse riding, museum hunt, visit history? Give us a clue and we can point the way

http://www.fodors.com/community/europe/alone-and-in-paris-for-the-first-time.cfm

http://www.fodors.com/community/europe/solo-female-traveler-in-paris.cfm

See these two threads that are also current for more advice on the topic....others have the same concerns but there is a ton of great advice!