There are many myths about Hitler, the Nazis, and inter-war Germany, That Hitler was elected is just the most prevalent.  I was just surprised to hear you repeat it.  The rise of Hitler and the Nazis is an almost perfect case study in how fear can be used to coopt a democracy.See here

As for De Gaul, he certainly was no Hitler, but he was on par with Franco in terms of dominating the government with his will.  Of course he used his war hero status to do it (no different than what Hitler did as he raised Germany up from the ashes of the Depression).

What are the sources confirming De Gaul as a dictator ?

Just what I was taught at the University of Kentucky.  I guess dictator seems harsh, but it also applies to FDR and Abraham Lincoln regarding the circumstances they faces while in power.  De Gaul had to rebuild France and keep order.  MacArthur was a dictator in Japan after the war.  Don't get caught up in the word dictator as always meaning malevolent and evil.  Sometimes it's necessary when order is on the verge of collapse.