"Justement, je mange une pomme."

Translation: Precisely, I am eating an apple.

[Caper]

What does this mean in English precisely? Is this in answer to a question like "what are you doing, eating an apple." Yes, exactly that, I'm eating an apple." Or is the precisely related to how the subject is eating the apple? A very precise movement of the teeth to extract all the pulp from around the core?

[Sitesurf]

The kind of conversation that could lead to "justement, je mange une pomme" could be as follows:

• you know, one apple a day keeps the doctor away (English idiom, translation: @ tu sais, une pomme par jour, c'est bon pour ta santé)
• precisely, I am eating an apple

[Hohenems]

Your first example. "Exactly that, I am eating an apple". If it was referring to how someone was eating an apple (strange thought/sentence), you would say "I am eating an apple (very) precisely".