I'm going to France in the summer?

"During" seems to imply continuity, but you only go to France at a single instant.

might it be more accurate if it is:
"During the summer, I'm going to go to France" ?

Agreed. When you do continuous + instant like that and put the instant in the continuous context, then "during" works.

I just asked my husband (native English speaker).

He says it sounds more natural for a native Eng speaker to say:
"In the summer, I'm going to go to France".
"During" could be use in a phrase such as "During lunch time, I do yoga" refers to, common actions that you do repetitively, such as "During meals, I tend to chew loudly" or "During the summer, I water my lawn more frequently".
On the other hand, probably the creator of this sentence was trying to say "each summer, I go to France". I would use "during" if that were the case.

Here is a website where they kind of explain this, but it is implicit.

http://www.ecenglish.com/learne...-for-and-while

BTW, I hope it helps! :)

I corrected it :) I hope it's right now...
I'm not good at English so I expected someone would correct me, I just did a loan translation of the Italian >.< please forgive me!

"Yaz boyunca Fransa'ya gideceğim."