An umbrella and a plastic poncho always come in handy because the weather in Paris might be a little bit unpredictable, and short showers are common all through the year.
Ear Plugs might not be of help because nightlife in Paris ends early, at about 2 am, principally.
To obtain Euros in advance is useful for paying for small items, gifts and food with cash, if desired.
Medical supplies are not needed during the stay in Paris. It is always cheaper to buy local brands. However, all prescription medications for allergies and other diseases of certain brands are a must-bring.
A pair of sunglasses should always be in hand.
A good and comfortable handbag for all necessary belongings and documents is a must. It must always be held in front because of the numerous pickpockets everywhere, especially in tourist spots, on the metro and RER network.