Should I first learn Frech or Arabic?

I think French would be easier to learn first because it is closer to English.

Better learn Frek first, because if you try Arabic, you may give up on learning foreign languages (plural).

Franch

Whichever you think useful.

First you should learn to spell "French" in English.

Beats me. They're both useful. Which do you think you would need the most?

Make your choices in accordance with YOUR preference(s), what you need / are looking for, personal use, etc.. Not ours.

I love both Arabic & French but i will advise you to learn arabic first so you can understand the civilsation, culture and you will appreciate it from your own perspective.
420 million people around the world speak Arabic, making it the sixth most spoken language.