Double opt-in with Contact Form 7

Hi,
I use Contact Form 7 for my subscription form.
When I send form, I receive the confirmation mail with a link to confirm the subscription. But the email is already added to my list as subscriber, even if I don’t click on the link.
The double opt-in is not possible with CF7 integration ? The subscription seems to be forced.
Is there a way to activate the double opt-in correctly for this ?

Thank you