Problem display

Enclose the while loop with a conditional:

$the_query = new WP_Query( array( 'p' => $id_film) );
if ( $the_query->have_posts() )
{
     while ( $the_query->have_posts() ):
        $the_query->the_post();
        // regular output
     endwhile;
     wp_reset_postdata();
}
else
{
    echo 'No movie data';
}