Thank you very much for your answers.
I use calibre to delete the lines spacing and to indent the first paragraphs lines.
Well it seems that my problem is about the Table of content. I decided to create it myself in Sigil but when i open it in my IPAD, the title page doesn't appear in the table of content. My title page is also my cover page.
I give you below what i typically have in sigil :
in the toc.ncx :
<?xml version="1.0" encoding="UTF-8" standalone="no" ?><!DOCTYPE ncx PUBLIC "-//NISO//DTD ncx 2005-1//EN" "http://www.daisy.org/z3986/2005/ncx-2005-1.dtd"><ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1">
<head>
<meta content="urn:uuid:4c54ff47-0464-4ee9-8993-5cbd15e79405" name="dtb:uid"/>
<meta content="0" name="dtb:depth"/>
<meta content="0" name="dtb:totalPageCount"/>
<meta content="0" name="dtb:maxPageNumber"/>
</head>
<docTitle>
<text>Try</text>
</docTitle>
<navMap>
<navPoint id="navPoint-1" playOrder="1">
<navLabel>
<text>Title</text>
</navLabel>
<content src="Text/titlepage.xhtml"/>
</navPoint>
</navMap>
</ncx>
And in the content.opf i have :
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<package xmlns="http://www.idpf.org/2007/opf" unique-identifier="BookId" version="2.0">
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns
pf="http://www.idpf.org/2007/opf">
<dc:identifier id="BookId" opf:scheme="UUID">urn:uuid:4c54ff47-0464-4ee9-8993-5cbd15e79405</dc:identifier>
<dc:title>Try</dc:title>
<dc:language>fr</dc:language>
</metadata>
<manifest>
<item href="toc.ncx" id="ncx" media-type="application/x-dtbncx+xml" />
<item href="Text/titlepage.xhtml" id="titlepage.xhtml" media-type="application/xhtml+xml" />
<item href="Images/cover.jpg" id="cover.jpg" media-type="image/jpeg" />
<item href="Text/Section0001.xhtml" id="Section0001.xhtml" media-type="application/xhtml+xml" />
</manifest>
<spine toc="ncx">
<itemref idref="titlepage.xhtml" />
<itemref idref="Section0001.xhtml" />
</spine>
</package>
Thank you very much for your help.
Ibn