Luggage and bags:
since Nancy is not that big as Paris... spending only a few days may be enough to know this place. so no need a big bags or luggages :)
Clothing/Shoes/Weather Gear: causual wear as what people wear there...
Toiletries and Medical Supplies: pack as what you want and need
Photo Equipment: please prepare those euqipment b4 you start off your trip
esp. the film is kinda expensive
Clothing/Shoes/Weather Gear: Well, I'd say that the weather in Nancy is pretty similar to the weather in W. Germany. The winters shouldn't be too cold and summers not too hot. A really strange thing about La Lorraine is the fact that whenever I went there it rained lol I don't know if that was because of me (lol just kidding) or if they just get a lot of rain this area. Anyway, I recommend you to bring an umbrella!