From knives to imitation pistols that fire blanks - over the past few months, more and more Germans have been arming themselves with self-defense products.

The sales volume doubled this year compared to 2014 in weapons stores across the country according to the German Association of Gunsmiths and Weapons Sellers (VDB), which conducted a random telephone survey among its 1,100 members.

The survey also found that more people applied for a special permit called a "small weapons license" which authorizes the user to carry pistols and revolvers for shooting blanks, gas and signaling ammunition. The license costs roughly 50 euros ($54), applicants have to be at least 18 years old and don't need to state a reason for their application.

In 2005, 2,710 people held such a license in the western city of Cologne. Since 2010, about 150 licenses were approved every year, Cologne police spokesman Dirk Weber told DW - but that number doubled to almost 300 this year, bringing the total number of licenses to 4,787.

Demand for stun guns and pepper spray was so high that in some cities, they were temporarily sold out.

Post-Paris fears

The reason, VDB director Ingo Meinhard said, seems to be that Germans' "personal security needs" have increased enormously.

Pepper spray is a popular non-lethal self-defense product

The "weapons boom" results from a mixture of a vague fear of terrorist attacks on the one hand, and a fear of burglaries and vandalism on the other, said German Police Union (DPoLG) chief Rainer Wendt.

As more and more asylum seekers enter Germany, creating new challenges for the police along with thousands of hours of overtime, people see the police force operating at the limits of its capacity, so perhaps they are concerned about whether the state can still protect them, they "fear everyday safety issues are being neglected," Wendt told DW.

This is an entirely subjective feeling, he added: "Germany is one of the safest countries in the world."

In the wake of the November 13 Paris attacks, and in view of the one million people that have entered Germany seeking refuge this year alone, Wendt said there certainly was a "general feeling of uncertainty" among the German public.

But citizens were wrong to believe they could protect themselves in a terrorist situation, the police union chief warned. Realistically, people without the necessary training would be overwhelmed if caught in a terrorist attack. Wendt also warned about relying on imitation revolvers that fire blanks, explaining that these weapons looked real and might lead to massive misunderstandings for police and security authorities involved in such incidents. Women often felt safe if they carried pepper spray when out at night, the police union chief added - but then, they rummage in their handbags to find it.

His advice: Keep a mobile phone handy, and be ready to call the police in an emergency - that's "more important than pepper spray."