Thank you all for your responses, I am not sure if I can confirm that the problem came from the third party application, but after some search and comparing things I found :
In the faulty mail, I found that all characters that are miss-displayed were replaced by the utf-8 "replacement character" =EF=BF=BD Searching on the web about quoted-printable, I found this site http://www.webatic.com/run/convert/qp.php which gave me the correct code for the characters with accent, using them in the faulty message fixed the problem. So somewhere along the way, the characters with accent were miss-encoded? could that be the application? Here some lines from the message : MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_76_1062807220.1510653473038" X-Priority: 1 ------=_Part_76_1062807220.1510653473038 Content-Type: image/jpeg; name="temp.gif" Content-Transfer-Encoding: base64 Content-Disposition: inline; filename=temp.gif Content-ID: <2F47766C7A454C4561674D51585556385369355378513D3D> R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAEALAAAAAABAAEAAAgEAAMEBAA7 ------=_Part_76_1062807220.1510653473038 *Content-Type: text/html;charset=utf-8Content-Transfer-Encoding: quoted-printable* <img src=3D"cid:2F47766C7A454C4561674D51585556385369355378513D3D" ><p><titl= e></title><span style=3D"font-size: 14pt;"></span><br type=3D"_moz"></p><p>= <meta name=3D"generator" content=3D"LibreOffice 5.4.2.2 (Windows)"></p><p><= meta name=3D"created" content=3D"2017-10-19T08:35:48.046000000"></p><p><met= a name=3D"changed" content=3D"2017-10-22T09:39:46.669000000"><style type=3D= "text/css"> =09=09@page { margin: 2.5cm } =09=09p { margin-bottom: 0.25cm; line-height: 120% } =09=09a:link { so-language: zxx }</style></p><p style=3D"line-height: 150%;= margin-bottom: 0cm;"><font face=3D"Tahoma, serif"><font size=3D"3" style= =3D"font-size: 12pt;"><b>DIVISION COMMERCIALE </b></font></font></p><= p style=3D"line-height: 150%; text-indent: 1.25cm; margin-bottom: 0cm;"><br= ></p><p align=3D"right" style=3D"line-height: 150%; margin-bottom: 0cm;"><f= ont face=3D"Tahoma, serif"><font size=3D"3" style=3D"font-size: 12pt;">14 N= ovember 2017</font></font></p><p style=3D"line-height: 150%; margin-bottom:= 0cm; margin-left: 7.75cm;"><br></p><p align=3D"center" style=3D"line-heigh= t: 150%; margin-bottom: 0cm;"><font face=3D"Tahoma, serif"><font size=3D"3"= style=3D"font-size: 12pt;">Madame </font></font></p><p ali= gn=3D"center" style=3D"line-height: 150%; margin-bottom: 0cm;"><br></p><p a= lign=3D"center" style=3D"line-height: 150%; margin-bottom: 0cm;"><br></p><p= style=3D"line-height: 150%; margin-bottom: 0cm; margin-left: 7.75cm;"><br>= </p><p style=3D"line-height: 150%; text-indent: -0.25cm; margin-bottom: 0cm= ;"><font face=3D"Tahoma, serif"><font size=3D"3" style=3D"font-size: 12pt;"= ><u><b>Objet</b></u></font></font> <font face=3D"Tahoma, serif"><font size= =3D"3" style=3D"font-size: 12pt;"><b>/ </b></font></font><font face=3D"Taho= ma, serif"><font size=3D"3" style=3D"font-size: 12pt;"> *Votre R=C3=A9clam=ation REF N=EF=BF=BD* In this example, this last line is in plain french : *Votre Réclamation* This sentence encoded in quoted-printable should be : *Votre R=C3=A9clamation* Any idea? Regards. <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Garanti sans virus. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> 2017-11-22 13:34 GMT+01:00 Wietse Venema <wie...@porcupine.org>: > wodel youchi: > > Hi, > > > > I need some clarification about Content-Type on an email. > > > > Who does fix the Content-Type of an email? > > The mail client? or the sending server or both? > > The sender (mail client). If text contains non-ASCII then the > client must specify > > Either: > > MIME-Version: 1.0 header > 8BITMIME option in the MAIL FROM command > content-type (including charset) header > content-transfer-encoding: 8bit header > > Or: > > MIME-Version: 1.0 header > content-type (including charset) header > content-transfer-encoding: quoted-printable or base64 header > > SEE also: > RFC 2045 (MIME: Format of Internet Message Bodies) > RFC 2046 (MIME: Media Types) > > > The problem : if we edit mails using the webmail or the mail clients > using > > non ASCII characters, they're well interpreted, but when using the > > application to send emails via our mail server, the non ASCII characters > > are not show properly. > > The receiver needs to know the charset and encoding. > > Wietse >
