I found the answer here. The query is simply :
$meta_query[] = [
'key' => 'adresse',
'value' => $_GET['field'],
'compare' => 'LIKE'
];
As it will search into the serialized (2D) array of the key adress
in the table post_meta from the DB any occurence of my $_GET['field']
value. That means it will also search into every key name and its value, but that’s enough for me.