ylebars

Hello everybody out there!

I have eventually found the solution. The following content of file “footer.php” satisfies me:

<?php
/**
 * The template for displaying the footer
 *
 * Contains the closing of the "site-content" div and all content after.
 *
 * @package WordPress
 * @subpackage Twenty_Fifteen_Child
 * @since Twenty Fifteen 1.0
 */

$language = pll_current_language('slug');
?>

	</div><!-- .site-content -->

	<footer id="colophon" class="site-footer" role="contentinfo">
		<div class="site-info">
			<?php
				/**
				 * Fires before the Twenty Fifteen footer text for footer customization.
				 *
				 * @since Twenty Fifteen 1.0
				 */
				do_action( 'twentyfifteen_credits' );
			?>

<?php
  if ($language == 'fr') {
    print "<p><a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-nd/4.0/\"><img alt=\"Creative Commons License\" style=\"border-width:0\" src=\"https://i.creativecommons.org/l/by-nc-nd/4.0/88x31.png\" /></a><br />Sauf mention du contraire, les contenus de ce site sont sous contrat <a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-nd/4.0/\">Creative Commons Attribution – Pas d’utilisation commerciale – Pas de modification 4.0 internationale</a>.</p>";
  }
  else {
    print "<p><a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-nd/4.0/\"><img alt=\"Creative Commons License\" style=\"border-width:0\" src=\"https://i.creativecommons.org/l/by-nc-nd/4.0/88x31.png\" /></a><br />Unless contrary mentioned, contents on this website are licensed under a <a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-nd/4.0/\">Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License</a>.</p>";
  }
?>

			<a href="<?php echo esc_url( __( 'https://ww.wp.xz.cn/', 'twentyfifteen' ) ); ?>"><?php printf( __( 'Proudly powered by %s', 'twentyfifteen' ), 'WordPress' ); ?></a>
		</div><!-- .site-info -->
	</footer><!-- .site-footer -->

</div><!-- .site -->

<?php wp_footer(); ?>

</body>
</html>

The problem is solved.

Best regards.

Yoann