It's always been a dream of mine to travel to Paris . I just want to know when is it the best time to go to Paris?
Usually in end May/June, when the weather is nice and the crowd not yet too dense. However this year the weather is expected to be bad during the whole summer, getting better only in September October.
Anytime in the warm months is good as long as you avoid the school holidays. That is a general rule for all European countries, in fact, and there is some variation from country to country. You cannot have any guarantees on the weather, though. I am sitting in Bordeaux right now and it is raining and quite cool which is not seasonable.
Summer's are usually extremely expensive. Especially August. All of Europe takes off of work and school and they will travel and it's usually to Paris so the price of the flights and hotels are double and sometimes triple. Not to mention how crowded it gets! September until mid October is still somewhat expensive but not as much and the whether is perfect because it won't be as hot. May and June are also beautiful.