Souci référencement SEO

 Line 16, Column 16: there is no attribute "property"

<meta property="og:locale" content="fr_FR" />

?

You have used the attribute named above in your document, but the document type you are using does not support that attribute for this element. This error is often caused by incorrect use of the "Strict" document type with a document that uses frames (e.g. you must use the "Transitional" document type to get the "target" attribute), or by using vendor proprietary extensions such as "marginheight" (this is usually fixed by using CSS to achieve the desired effect instead).

This error may also result if the element itself is not supported in the document type you are using, as an undefined element will have no supported attributes; in this case, see the element-undefined error message for further information.

How to fix: check the spelling and case of the element and attribute, (Remember XHTML is all lower-case) and/or check that they are both allowed in the chosen document type, and/or use CSS instead of this attribute. If you received this error when using the <embed> element to incorporate flash media in a Web page, see the FAQ item on valid flash.
Error Line 86, Column 3445: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

...ErkJggg==" border="0" alt="Album" /><br/><h2 class="title1">Album</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").
Error Line 87, Column 7809: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

...CYII=" border="0" alt="Contact" /><br/><h2 class="title1">Contact</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").
Error Line 88, Column 4077: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

...C" border="0" alt="Actualité" /><br/><h2 class="title1">Actualité</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").
Error Line 89, Column 3731: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

... border="0" alt="Prestation" /><br/><h2 class="title1">PME</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").
Error Line 90, Column 4016: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

... border="0" alt="Entreprise" /><br/><h2 class="title1">Entreprise</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").
Error Line 91, Column 3802: document type does not allow element "h2" here; missing one of "object", "applet", "map", "iframe", "button", "ins", "del" start-tag

..."0" alt="Mention légale" /><br/><h2 class="title1">Mention Légale</h2></a></td>

?

The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "<font>").