If you plan to bring a computer with you from home, you should check with the manufacturer to determine if you will need a transformer in France and, if so, what kind. (Electrical current in France is 220 volts with a line frequency of 50 hertz cycles per second; there are transformers that correct voltage differences). If you are coming from Mexico, Brazil, North America (and perhaps other countries), bring an adapter and converter. Adaptaters will allow you to plug in your computer but you will also need the converter to transform the volts. Some computer manufacturers, like Apple, have an automatic conversion feature.
Purchasing computer equipment in France can be expensive, though prices have been steadily dropping. It is possible to purchase a good notebook for €250. The keyboard will be French.
Be sure to carry your medication and prescriptions in your hand luggage so that you have enough to carry you through in the event that your luggage is lost. Ask your doctor if the medication you are currently taking is available in France and if not, what substitutes you can take.
Crazy as it may seem, France being one of the food capitals of the world, there may be items that you cannot find here that are commonly found at home. Experience has shown us that Mexicans crave a type of tortilla or hot sauces (La Costeña, Herdez, etc.) that aren't available in France, and Finns miss salmiakki.
If it's easy to pack, you may want to bring a jar of your favorite spice, or pack of your favorite candy to have when you're missing it or to introduce to new friends. Remember it will come in handy at the international dinner. Bring recipes too!
The climate in Lyon has been rather unpredictable for the past few years. In the summer it can be unbearable hot and dry or cool and rainy. While that doesn't help you know how to pack, it is safe to say that you will need an umbrella.
In the winter, you will need a warm coat, gloves, and a hat (even if you are coming from Canada or Russia). While the winter may be shorter than you are used to, it will probably be cold for at least a few weeks.