Encoding error in sent mails

I’m trying to send an HTML email with Rails so I have a mailer’s view with the format .html.haml.

My email is written in French so it contains accentuated characters.

In the terminal, the server shows me the following:

I'm trying to send an HTML email with Rails so I have a mailer's view with
the format .html.haml.

My email is written in French so it contains accentuated characters.

In the terminal, the server shows me the following:

-----------

Message-ID: <4e61088339572_467e3ffda3c5c8185d2@nelson4.home.mail>
Subject: =?UTF-8?Q?R=C3=A9ponse_=C3=A0_un_de_vos_commentaires_sur_Syrinxoon?=
Tuts
Mime-Version: 1.0
Content-Type: text/html;
charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE html>
<html>
<head>
<title>R=C3=A9ponse =C3=A0 un de vos commentaires sur Syrinxoon Tuts<=

This actually looks normal, given that the Content-Transfer encoding
is quoted-printable.
=C3=A9 is quoted printable speak for the pair of bytes 0xC3, 0xA9,
which is the utf8 sequence for acute. Because = is special in this
encoding scheme, any literal = has to be encoded as =3D. Is your mail
client not displaying this properly?

Fred

I did not have tried to display it in my mails client because I’m still in development.
You think the client will not be disturbed by this?

I don't believe so, but you should definitely try that since it's what
your users will be doing. By the way, the mailcatcher gem is pretty
good for viewing emails sent in development)

Fred

I will investigate that.

Thank you Frederick.