import smtplib
from email.mime.text import MIMEText

USERNAME = 'xxx@gmail.com'
PASSWORD = 'xxx'


def send_mail (to):
	msg = MIMEText('coucou')
	msg['Subject'] = 'Salut ma couille 2'
	msg['From'] = "xxx@gmail.com"
	msg['To'] = to
	s = smtplib.SMTP('smtp.gmail.com:587')
	s.ehlo()
	s.starttls()
	s.login(USERNAME, PASSWORD)
	s.sendmail("xxx@gmail.com", [to], msg.as_string())
	s.quit()

def main():
	send_mail('xxx@étudiant.fr')  # << here, the é is the problem

if __name__ == '__main__':
	main()