DateTime::createFromFormat requires the second parameter to be a timestamp and ACF returns an already formatted date that depends on the return/display format you’ve set for the field. You can’t use this function.
// returns unformatted date
$date = get_field('jour_de_levenement', false, false);
// convert it to a time
$time = strtotime($date);
<span class="day"><?php echo date('d', $time); ?></span>
<span class="month"><?php echo date('F', $time); ?></span>
<span class="year"><?php echo date('Y', $time); ?></span>
