It totally depends on your schedule and budget. Spring may be the best choice, but during this time the city is very full with tourists and prices will probably be higher. If you like crowds and can afford the expenses, then spring is the best time.
Summer is also good. Due to school schedules, students like to visit Paris in the summer. In the fall, crowds will be smaller and you can enjoy the change of the seasons.
Winter is not so good as the city will be covered with snow, but for a romantic couple, it can still be a wonderful time to visit the city. Source: great-vacations-travel-guide.com/paris-f....
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.