Infopompiers defines risque courant as:
"Risque se caractérisant par une forte probabilité d’occurrence associée à une gravité faible en termes d’effets sur les personnes, les biens et l’environnement d’un point de vue de la société prise dans son ensemble."
https://infopompiers.com/Lexique pompiers/risque-courant/

As such, from the literature I've come across in the UK, there seems to be a likelihood of fire/severity of harm risk assessment matrix that is in use for fire safety (see https://www.sirentraining.co.uk/fire-safety-risk-assessment/ or https://www.merton.gov.uk/assets/Documents/www2/fire_safety_...

The Merton link in particular gives a good definition which seems to fit your context:
"The phrase ‘Fire Risk’ can be defined as the Likelihood of a fire occurring multiplied by the Severity of the fire i.e. the ‘harm potential’ and consequences in terms of loss of life, fire spread, damage etc."

On that basis, I'd go with something along the lines of "high fire risk and low harm potential".

Hope that helps!

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Note added at 24 mins (2022-06-10 12:20:03 GMT)
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I'll be the first to admit that it's not the most succinct! ;)

Not intended for grading: I'm reposting this here because the Discussion box is too short.

"Isolement par rapport aux tiers: Type M = à risques particuliers. Défendu par un SEATS*, considéré à risques courants "
* Système d’Extinction Automatique de Type Sprinkler

This text and yours seem to suggest that the hazard level is determined by the fire protection system, which seems arse about tilt to me. (but see below).

Fortunately there is this:
"Le sprinkler est un système d’extinction comportant une tête contenant une ampoule ou un fusible qui éclate sous l’effet de la chaleur dégagée par un début d’incendie. Le flux d’eau est alors libéré pour contenir l’incendie jusqu’à l’intervention des secours ou la fermeture manuelle des vannes.
Le dimensionnement du réseau se fait grâce à l’analyse du RISQUE À PROTÉGER, classifiés selon la règle R1 de l’APSAD :
• Risque à faible potentiel calorifique (RFPC)
• Risques Courants (RC)
• Risques Très Dangereux (RTD)
• Risques Spéciaux (RS)"

which is in line with the English below:

"Within the LPC [*] Sprinkler Rules system design is defined as either LIGHT, ORDINARY OR HIGH HAZARD.
Light hazard systems are typically installed in premises with low fire loads and of low combustibility e.g. hospitals, schools, etc.
ORDINARY HAZARD systems are installed in premises where medium fire loads are present or manufactured e.g. engineering risks, food & beverage, retail, etc. 4 of 5 Automatic Sprinklers AIG Insight | UC161105 Automatic Sprinklers Insight Within the ordinary hazard classification there are 4 sub groups OH1 to OH4 with increasing designed areas of operation - in the majority of cases OH3 design is the default standard used.
High hazard systems protect either Process or Storage risks with high fire loads. Both categories are divided into sub groups 1 to 4 with increasing requirements in respect of design density of discharge and area of operation. High hazard process risks range from paint manufacturers classed as HHP group1 to firework manufacturers classed as HHP group 4.
[* The LPC (Loss Prevention Council) Rules for Automatic Sprinkler Installations is the primary design code specified by UK insurers]

Re. classification with/without sprinklers, the texte below (image) makes things clear.