diff --git a/htdocs/core/class/html.formmail.class.php b/htdocs/core/class/html.formmail.class.php
index 4c77566eeed..c23545a34c9 100644
--- a/htdocs/core/class/html.formmail.class.php
+++ b/htdocs/core/class/html.formmail.class.php
@@ -85,7 +85,7 @@ class FormMail extends Form
 	public $toid;
 
 	/**
-	 * @var string replyto name
+	 * @var string 	Reply-to name
 	 */
 	public $replytoname;
 
@@ -95,20 +95,25 @@ class FormMail extends Form
 	public $replytomail;
 
 	/**
-	 * @var string to name
+	 * @var string 	To name
 	 */
 	public $toname;
 
 	/**
-	 * @var string to email
+	 * @var string 	To email
 	 */
 	public $tomail;
 
 	/**
-	 * @var string trackid
+	 * @var string 	Track id
 	 */
 	public $trackid;
 
+	/**
+	 * @var string	If you know a MSGID of an email and want to send the email in reply to it. Will be added into header as In-Reply-To: <...>
+	 */
+	public $inreplyto;
+
 	public $withsubstit; // Show substitution array
 	public $withfrom;
 
@@ -449,6 +454,7 @@ class FormMail extends Form
 				$out .= '<input style="display:none" type="submit" id="sendmailhidden" name="sendmail">';
 				$out .= '<input type="hidden" name="token" value="'.newToken().'" />';
 				$out .= '<input type="hidden" name="trackid" value="'.$this->trackid.'" />';
+				$out .= '<input type="hidden" name="inreplyto" value="'.$this->inreplyto.'" />';
 			}
 			if (!empty($this->withfrom)) {
 				if (!empty($this->withfromreadonly)) {
@@ -458,7 +464,7 @@ class FormMail extends Form
 			}
 			foreach ($this->param as $key => $value) {
 				if (is_array($value)) {
-					$out .= "<!-- param key=".$key." is array, we do not output input filed for it -->\n";
+					$out .= "<!-- param key=".$key." is array, we do not output input field for it -->\n";
 				} else {
 					$out .= '<input type="hidden" id="'.$key.'" name="'.$key.'" value="'.$value.'" />'."\n";
 				}
diff --git a/htdocs/core/tpl/card_presend.tpl.php b/htdocs/core/tpl/card_presend.tpl.php
index 9e0a38bee39..0376a5e85c9 100644
--- a/htdocs/core/tpl/card_presend.tpl.php
+++ b/htdocs/core/tpl/card_presend.tpl.php
@@ -147,7 +147,8 @@ if ($action == 'presend') {
 		$formmail->fromtype = 'special';
 	}
 
-	$formmail->trackid = $trackid;
+	$formmail->trackid = empty($trackid) ? '' : $trackid;
+	$formmail->inreplyto = empty($inreplyto) ? '' : $inreplyto;
 	$formmail->withfrom = 1;
 
 	// Fill list of recipient with email inside <>.
diff --git a/htdocs/recruitment/recruitmentcandidature_card.php b/htdocs/recruitment/recruitmentcandidature_card.php
index c1a4ca94045..3d11afc5900 100644
--- a/htdocs/recruitment/recruitmentcandidature_card.php
+++ b/htdocs/recruitment/recruitmentcandidature_card.php
@@ -652,6 +652,7 @@ if ($object->id > 0 && (empty($action) || ($action != 'edit' && $action != 'crea
 	$defaulttopic = 'InformationMessage';
 	$diroutput = $conf->recruitment->dir_output;
 	$trackid = 'recruitmentcandidature'.$object->id;
+	$inreplyto = $object->email_msgid;
 
 	include DOL_DOCUMENT_ROOT.'/core/tpl/card_presend.tpl.php';
 }