If you find that hard or do not understand the dialects at least learn to recognise them when written down. Knowing what the sign is for a bus stop, cafe, phone, police or hostel could be very helpful, particularly when arriving somewhere at night.
Try not to wear highly visible expensive jewellery this could make you a target for opportunists. Be aware when going out on a night out, always travel with someone or take a taxi.
Politics can be a delicate subject in France, when walking around the city try not to wear clothing that makes a specific statement, for example from a political movement and avoid the subject in general conversation.
Hiring a car or driving in France can be a challenging experience, be aware that you have to drive on the right hand side of the road. This can often be harder if you are using a right hand drive car. Speeding can results in on-the-spot fines. Make sure you have enough euros to cover the charges.