Hi and welcome.
A week isn't much to travel so far. In Europe Spring is only just starting and with you living in Nigeria I guess you don't fancy cold and wet, right?

That somewhat narrows down your choice of where to go.
Outside summer I recommend you stay close to the Mediterranean coast, but no too close.
As to what kind of trip to take I think you have to make up your own mind.
If you are capable of riding a scooter through Lagos then you won't have any trouble travelling with a guided tour. Remember: you do this trip to enjoy yourself and see something, so you don't have to ride IN the group. Get a map (if the operator doesn't provide one, which she should), know the meeting places and ride at your own pace. Whether you can find a guided tour in your language at a suitable time is a different matter.
For renting in France I know of one outfit, although I have never used them:
http://www.holiday-bikes.com/accueil/main_us.htm
I should also put in a shameless plug here for "our" region: we do live in the bikers' paradise here. Spring is starting right now, the flowers are coming out and temperatures in the last two days have shot up to about 20°C.
Make sure you bring your own bike gear, helmet, boots, etc. as you won't be able to rent it.
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Salut from Southern France, the bikers' paradise,
Peter.
[This message has been edited by beddhist (edited 16 March 2005).]