The source given above is the old municipal website of Cisnădie. The updated URL is
http://www.cisnadie.ro/. Further research yields interesting
historical details on the region, which has an old German / Protestant
background.
The municipality of Cisnădie (in German, Heltau; in Transylvanian
Saxon, Hielt; in Hungarian, Nagydisnód) is located
in Transylvania (in Romanian, Ardeal or Transilvania; in German, Siebenbürgen; in Hungarian, Erdaly), central Romania, 10 km south of
Sibiu (in German, Hermannstadt). The area of the municipality is
13,856.7 ha, including the towns of Cisnădie proper (272 ha) and Cisnădioara (41.7 ha). The population of the municipality is 15,615.
The first mention of a settlement in today's Cisnădie dates back to
1204, whereas the oldest written mention of Heltau dates back to 1323.
In 1385, a student from Cisnădie entered the University of Vienna. The
town was granted market right in 1500 following a visit by King of
Bohemia and Hungary Vladislav II (1456-1516). From the XVth to the
XVIIth century, the town was often sacked by the Turks and the
Wallachians. In 1734, 125 Landler settled in Heltau. The Landler were
Protestants deported from Salzkammergut (the region around Salzburg,
Austria) to Transylvania by Emperor Charles VI (1685-1740); the region
of Hermannstadt was the only Protestant area left in the
Austro-Hungarian Empire. The Landler were sent there to resettle the
region scoured by the Turks and the black plague.
In the XIXth century, Heltau became famous for its textile industry; in
1919, the biggest textile factory in Transylvania was set up in the
town by Gromen and Herbert. In 1941, ethnic Germans represented c. 70%
of the population of the town. In the 1950s, massive emigration to
Germany started, which peaked after the 1989 revolution. The town of Cisnădie (as well as Sibiu and a few other towns and villages in the
neighborhood) is ran today by the "Demokratisches Forum der Deutschen
in Rumänien" (DFDR - Democratic Forum of the Germans in Romania), the
political party representing the ethnic Germans in Romania, which was
founded at the end of 1989.
The flag of Cisnădie is shown on the old municipal website (
http://www.cisnadie.ro/index-old.php
) as vertical, vertically
divided blue-red-blue with the municipal arms in the middle. The arms
are made of a shield azure charged with an escutcheon argent bearing a
charge I cannot identify (something like a shield with a vertical
spear) standing on a wall gules, supported by two lions and surmounted
by a crown or. The whole shield is surmounted by a mural crown argent. I
imagine that these arms were granted by King Vladislav II when he
granted market right to the city, but I have not found evidence of
that.
The new municipal website shows a photography of the city hall
( http://www.cisnadie.ro/ro/organigrama.htm ), on which the municipal
flag can be guessed as used horizontally, like the other flags
displayed there (Romania, France, Germany, Hungary, European Union));
the arms are not visible but it can be safely assumed that they are
placed vertically in the middle of the red stripe. Photographs taken during the celebration of the 800th anniversary of
the city ( http://www.cisnadie.ro/foto3/foto-11.htm and
http://www.cisnadie.ro/foto3/foto-12.htm
) show the municipal flag with
the blue shade quite lighter than on the Romanian and French flags.