Preview of second images

Hi, I see that your theme also uses Owl Carousel. When I view page source I see the following line:
<script type=’text/javascript’ src=’https://www.atelier-olivierbourgeois.com/wp-content/themes/boston-custom/assets/js/owl.carousel.min.js?ver=1.3.3′></script&gt;

I wonder if there is a clash. Could you try activating another (the ‘Twenty Seventeen’) theme to test. You can always reactivate your Boston theme after the test without any issue.