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Offences against life and limb

Self-defence and necessity: when a defence remains unpunished (Sections 3, 10 StGB)

Self-defence under Section 3 StGB and excusing necessity under Section 10 StGB: requirements, the excess of self-defence out of fear and fright and putative self-defence.

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25 June 2026 · Mag. Christopher Angerer, Rechtsanwalt

After an altercation the question often arises whether one’s own conduct was justified by self-defence. Anyone who is attacked and defends themselves may remain free of criminal liability. The limits are narrow, however, and precisely in the turmoil of a confrontation the right degree is hard to gauge. For accused persons the decisive point is whether a self-defence situation existed and whether the defence was necessary.

This post explains from a legal perspective when self-defence under Section 3 StGB justifies a defence, what applies in the case of an excess of self-defence, how mistakenly assumed self-defence is assessed and when the excusing necessity under Section 10 StGB applies. This is general information, not advice in an individual case.

Which situation applies to you?

Four situations, one clear next step.

Whether a defensive act remains unpunished depends on whether a self-defence situation existed and whether the defence was necessary and proportionate. Choose your situation and you will receive the key points and the next concrete step.

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01 Question 1

What does your case involve?

Whether a defensive act remains unpunished depends on whether a self-defence situation existed and whether the defence was necessary and proportionate. Choose your situation and you will receive the key points and the next concrete step.

All paths at a glance

Overview of all answers.

01

Defence after an attack: examine the self-defence situation and the necessity of the response.

Self-defence under Section 3 StGB justifies a defence against a present or immediately threatening unlawful attack on certain legal interests such as life, health, physical integrity, freedom or property. Anyone who chooses the necessary defence in such a situation acts lawfully and therefore without criminal liability.

From a legal perspective the decisive point is to record exactly what happened: who started it, what the threat was and what response was required. Do not make any statement on the substance before you have inspected the file and taken advice.

In depth: the requirements of self-defence →
02

Possible excess of self-defence: examine the extent of the response and the emotional state.

If the necessary extent of the defence is exceeded or an obviously disproportionate means is used, there is an excess of self-defence. If this happens out of dismay, fear or fright, the act is punishable under Section 3 para 2 StGB only if the excess is based on negligence and negligent commission is subject to a penalty.

From a legal perspective the emotional state in particular must be examined carefully, because it can determine criminal liability. Record how you experienced the situation and how quickly everything unfolded.

In depth: the excess of self-defence →
03

Mistakenly assumed self-defence: putative self-defence is assessed separately.

Anyone who mistakenly assumes they are being attacked, although objectively no self-defence situation exists, is in a situation of putative self-defence. This constellation is not assessed under the rules of genuine self-defence but as a mistake. Depending on whether the mistake was avoidable, a penalty for a negligence offence may come into consideration.

From a legal perspective what matters is which indications of an attack were present and whether the misjudgement was understandable. This classification should be carried out carefully.

In depth: putative self-defence →
04

Acting in an emergency: the excusing necessity under Section 10 StGB.

If it was not about repelling an attack but about averting an immediately threatening danger, the excusing necessity under Section 10 StGB comes into consideration. It requires that an immediately threatening significant detriment to oneself or another was to be averted and that no other conduct was reasonable.

From a legal perspective the proportionality between the detriment averted and the detriment inflicted is central. Record what danger existed and what alternative courses of action there were.

In depth: the excusing necessity →

The requirements of self-defence under Section 3 StGB

Self-defence under Section 3 StGB is a ground of justification. Anyone who meets the requirements does not act unlawfully and remains free of criminal liability.

Self-defence situation. What is required is a present or immediately threatening unlawful attack on certain interests capable of being defended. The law protects life, health, physical integrity, freedom and property, both one’s own and those of another person.

Defensive act. Only the necessary defence is justified, that is the means that repels the attack safely and definitively and is at the same time the gentlest among the equally effective ones. There is in principle no duty to flee.

Intention to defend. The person defending must act in awareness of the self-defence situation, that is in order to repel the attack.

Limits of the necessary defence

Self-defence is not without limits. The law sets out one important restriction.

Disproportionate defence where the detriment is minor. The defence is not justified if the person attacked is threatened only with a minor detriment and the defence is disproportionate, in particular because of the severity of the impairment of the attacker that is necessary to repel it. There is therefore a certain requirement of proportionality where only a minor legal interest is threatened.

The necessary extent. If several effective means of defence are available, the gentlest must be chosen. Anyone who without need resorts to a markedly more dangerous means exceeds the necessary extent.

From a legal perspective the precise reconstruction of the threat is important, because the necessity and proportionality of the response are measured against it.

Excess of self-defence under Section 3 para 2 StGB

If the limit of the necessary defence is exceeded, the act is not automatically punishable.

Exceeding the extent. An excess of self-defence exists if the necessary extent of the defence is exceeded or an obviously disproportionate means is used.

Asthenic affects. If the excess happens out of dismay, fear or fright, the offender is to be punished under Section 3 para 2 StGB only if the excess is based on negligence and negligent commission is subject to a penalty. These so-called asthenic affects can therefore lead to freedom from criminal liability.

From a legal perspective this rule is often decisive, because it takes account of the situation in the turmoil of a confrontation.

Putative self-defence: mistakenly assumed self-defence

Not every supposed self-defence situation is a genuine one.

Mistake about the self-defence situation. Anyone who mistakenly assumes they are being attacked, although objectively no attack exists, acts in putative self-defence. This constellation is assessed under the rules on mistake.

Avoidability of the mistake. If the mistake was unavoidable, the person acting remains free of criminal liability. If it was avoidable, that is recognisable with due attention, a penalty for a negligence offence comes into consideration, in so far as such an offence is subject to a penalty.

From a legal perspective what matters is which concrete indications pointed to an attack and whether the misjudgement was understandable.

The excusing necessity under Section 10 StGB

To be distinguished from an attack is the situation of danger that concerns necessity.

Requirements. Under Section 10 StGB a person acts in an excused manner if they commit an act subject to a penalty in order to avert an immediately threatening significant detriment from themselves or another, provided that the harm threatened by the act does not weigh disproportionately more heavily than the detriment it is intended to avert, and provided that in the offender’s position no other conduct could be expected of a person bound to the legally protected values.

Limits. Necessity does not excuse if the offender exposed themselves to the danger without a ground recognised by the legal order, or if they were required to accept the danger. If the offender is mistaken about a circumstance that would excuse them, they can be punished only for negligent commission.

From a legal perspective the proportionality between the detriment averted and the detriment inflicted is the central point of examination.

The most common mistakes after a self-defence situation. Assuming that every reaction to an attack is automatically justified. Failing to record exactly what happened, so that it later remains unclear who attacked. Making a statement as an accused person without inspecting the file and misrepresenting the self-defence situation. In all cases the rule is: document the sequence of events and your own perception early and precisely.

Frequently asked questions

What you need to know about self-defence and necessity.

When is a defence justified by self-defence? +

Self-defence under Section 3 StGB justifies the necessary defence against a present or immediately threatening unlawful attack on life, health, physical integrity, freedom or property. Only the means that repels the attack safely and is at the same time the gentlest among the equally effective ones is justified.

Do I have to flee from an attack? +

There is in principle no general duty to flee in self-defence. Anyone who is unlawfully attacked may defend themselves. The restriction must be observed, however, that where only a minor detriment threatens, the defence must not be disproportionately severe.

What happens if I exceeded the limits of self-defence? +

If the necessary extent is exceeded or an obviously disproportionate means is used, there is an excess of self-defence. If this happens out of dismay, fear or fright, the act is punishable under Section 3 para 2 StGB only if the excess is based on negligence and negligent commission is subject to a penalty.

What applies if I only felt threatened? +

Anyone who mistakenly assumes a self-defence situation acts in putative self-defence. This is assessed under the rules on mistake. If the mistake was unavoidable, the person acting remains free of criminal liability. If it was avoidable, a penalty for a negligence offence comes into consideration.

How does necessity differ from self-defence? +

Self-defence concerns repelling an unlawful attack by a person. The excusing necessity under Section 10 StGB concerns rescue from an immediately threatening danger and requires, among other things, that the threatening harm does not weigh disproportionately more heavily than the detriment averted and that no other conduct was reasonable.

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