No, it was never Von Paulus tho you will find a huge number of sites which will list him as that. Just because it is on the internet (or TV) doesn’t make it accurate.
The fact is that he came from a family with no claims to the nobility. That fact held him back for much of his career.
He was also known as von Paulus. I’m not going by the the internet solely or TV. I have always read about him as von Paulus. Maybe you’re right, I could be wrong.
“Friedrich Paulus Biography
Friedrich Paulus (September 23, 1890 - February 1, 1957) was a German general, later promoted to field marshal, during World War II. He was commander of the German 6th Army during the Battle of Stalingrad. He was also known as von Paulus. The “von” in the name is not authentic, a misconception presumably based on the fact that for many German “noble families” the career of officer in the armed forces was traditionally popular for at least one of their sons. (Many German officers and generals carried the “von” in their names. Paulus was the son of a minor official, one reason why he was promoted by Hitler who saw himself in the same light - a genius from humble background.)”
Even LIFE magazine calls him von Paulus. Not necessarily a mark of nobility. He was born in Prussia afterall.
“Life magazine photos
Have a look at this amazing repository of classic photographs at Life.com. Below are a few that came up when I searched under Oppenheimer, von Neumann and Stalingrad. The caption for the bottom photograph is “1st February 1943: German commander of the 6th Army, Field Marshal Friedrich von Paulus (1890 - 1957), surrendering after his troops were besieged at Stalingrad.”
I could be wrong though.