I just downloaded your theme from here:
https://www.itcouldbethisone.com/category/margot/
The footer is not encoded. Your theme folder is named margot-10. The folder from the source above is named margot. The changelog says it was developed on the WP 2.0 series. Been around a while, I guess.
I suspect you have an altered copy. Do as you wish with it, but here is the actual entire contents of footer.php
<!-- begin footer -->
<div class="reset"></div>
<?php wp_footer(); ?>
<!-- end footer -->
<div id="bottom-container"></div>
</div><!-- // end container -->
<div id="second-bloc">
<div id="top-second-bloc"></div>
<div id="inside-second-bloc">
<div class="second-tile">
<div class="owner"><a href="https://www.dfc-e.com/metiers/pme/sage-gestion/formation-sage/" title="Formation SAGE">Formation SAGE</a> <span>©</span> <?php bloginfo('administrator'); ?></div>
<div class="footer-reset"></div>
</div>
</div>
<div id="bottom-second-bloc"></div>
</div>
</div><!-- // whole -->
</body>
</html>
I guess I would be hesitant to use it regardless of the source.