I can leave you a bridge here too, if someone decides to translate or maybe you could do it:
"Thank you, too! (I also thank you)
You are lovely(wonderful, adorable) and impressingly beautiful!
(What a ) pity I don't know yet French.
Lots of kisses, "
I am always sort of nervous when I translate into foreign languages because there is always a difference between the way in which a native expresses itself and the way a foreigner "finds" his words and this is why I preffer to translate only the 100% sure texts for me.
Just a detail : I translated "beautiful" using the female gender ( "belle" ), does Finnish use genders, and is it possible to assume this message is addressed a woman?
I am sure it is adressed to a woman, but indeed, in Finnish there are no genders, but there are words used when talking about women or men: "kaunis" for women and "komea" (handsome) for men.