if you suspect then you don't know

It is silly to suspect DBI has a problem with unicode, if DBI did, it would manifest for OP without PAR

DBI does not have a problem with unicode in a dsn, it simply doesn't care,

As previously stated, the problem as reported by OP is unreproducible

This is where the error comes from

    # extract dbi:driver prefix from $dsn into $1
    $dsn =~ s/^dbi:(\w*?)(?:\((.*?)\))?://i
            or '' =~ /()/; # ensure $1 etc are empty if match fails
    my $driver_attrib_spec = $2 || '';

    # Set $driver. Old style driver, if specified, overrides new dsn s
+tyle.
    $driver = $old_driver || $1 || $ENV{DBI_DRIVER}
    or Carp::croak("Can't connect to data source '$dsn' "
            ."because I can't work out what driver to use "
            ."(it doesn't seem to contain a 'dbi:driver:' prefix "
            ."and the DBI_DRIVER env var is not set)");
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