Problem migrate frensh characters from Interbase to Mysql

[mourad]

Hello everybody, I've written a Qt program which migrate data from an Interbase database to a MySQL database.
It works fine but I've a problem with frensh characters like (é, è, à , etc).
Those charcaters are fine in the interbase database, but after executing the select request to have data and I display the data I've selected those characters are displayed as " ? ".
This my connection function

QSqlDatabase db = QSqlDatabase::addDatabase(driver, name);
    db.setHostName(host);
	db.setDatabaseName(path);
    db.setUserName(user);
    db.setPassword(pwd);
	if(driver == "IBASE")
		db.setConnectOptions("ISC_DPB_LC_CTYPE = LATIN1");
 
	if(!db.open())
	{
		qCritical() << "Erreur Ouverture base de données : " << db.lastError().text();
		return false;
	}
	return true;

QSqlDatabase db = QSqlDatabase::addDatabase(driver, name);
    db.setHostName(host);
	db.setDatabaseName(path);
    db.setUserName(user);
    db.setPassword(pwd);
	if(driver == "IBASE")
		db.setConnectOptions("ISC_DPB_LC_CTYPE = LATIN1");

	if(!db.open())
	{
		qCritical() << "Erreur Ouverture base de données : " << db.lastError().text();
		return false;
	}
	return true;

To copy to clipboard, switch view to plain text mode 

.
Can anyone tel me where I'm wrong and how to do resolve this problem.
Knowing that I've tried to user QTextCodec like

QTextCodec *codec = QTextCodec::codecForName("LATIN1");
		qDebug() << codec->toUnicode(q1.value(1).toByteArray());

QTextCodec *codec = QTextCodec::codecForName("LATIN1");
		qDebug() << codec->toUnicode(q1.value(1).toByteArray());

To copy to clipboard, switch view to plain text mode 

but I've always the same result " ? ".
Many thanks in advance.
Best Regurads.