ACCA - Association Communale de Chasse Agréée
AF - Allocations Familiales
ALP - Accueil loisir périscolaire
APHP - Assistance Publique-Hôpitaux de Paris
ARS - Allocation Rentrée Scolaire or Agence Régionale de Santé
AVC - Accident Vasculaire Cérébral (Stroke)
CAF - Caisse Allocations Familiales
CARSAT - Caisses d’Assurance Retraite et de la Santé au Travail
CCSS - Caisse Commune de Sécurité Sociale/Centre communal d’action sociale
CE1 - Cours Élémentaire 1ère Année (School 7-8 ans).
CE2 - Cours Élémentaire 2ième Année (School 8-9 ans)
CEG - Collège d’Enseignement Général (now known simply as Collège)
CIATE - Communauté Intercommunale d’Aménagement du Territoire
CF - Complément Familiale
CHU - Centre Hospitalier Universitaire
CHRU - Centre Hospitalier Régional Universitaire
CIAT - Comité Interministériel d’Aménagement du Territoire
CM1 - Cours Moyen 1ère Année (School 9-10 ans)
CM2 - Cours Moyen 2ème Année (School 10-11 ans)
COC - Certificat de Conformité (Européen) for cars imported from abroad
CP - Cours Préparatoire (School 6-7 ans)
CPAM - Caisse Primaire d’Assurance Maladie
CRAM - Caisse Régionale d’Assurance Maladie
CT - Contrôle technique (MOT)
DMLA - Dégénérescence Maculaire Liée à l’âge (AMD in English)
DUP - Déclaration d’Utilité Publique
EFS - Établissement français du sang (Blood Transfusion service)
ENA - École National d’Administration
ENS - École Normale Supérieure
FDAEC - Fond Départemental d’aide à l’Equipement des Communes
GIGN - Groupe d’Intervention de la Gendarmerie Nationale
GIHP - Groupement pour l’Insertion des Personnes Handicapées Physiques
GIPN - Groupe d’Intervention de la Police Nationale (same as RAID but in
overseas departments)
GRIMP - Groupe de Reconnaissance et d’Intervention en Milieu Périlleux
GS - Grand Section (School 5-6 ans)
LGT - Lycée Général et Technique
LP - Lycée Professionnel
MDR - Mort de Rire
MS - Moyenne Section (School 4-5 ans)
ONAC - Office National des Anciens Combattants et Victimes de Guerre
ONF - Office National des Forêts
PAF - Paysage Audiovisuel Français
PAJE - Prestation d’Accueil du Jeune Enfant
PGHM - Peloton de Gendarmerie de Haute Montagne
PGM - Peloton de Gendarmerie de Montagne
PLU - Plan Local d’Urbanisme
PNR - Parc Naturel Regional
PPMS - Plan particulier de mise en sûreté (face aux risques majeurs) - Applies to schools.
PS - Petite Section (School 3-4 ans)
PSIG - Peloton de surveillance et d’intervention de la gendarmerie (Same as GIGN, RAID, but at local (department) level
RAID - Recherche, Assistance, Intervention, Dissuasion (crack police unit)
RSI - Régime Social des Indépendants
SAMU - Service d’Aide Médicale Urgente
SMIC - Salaire Minimum Interprofessionnel de Croissance
SMUR - Service Mobile d’Urgence et de Réanimation
SNCF - Société Nationale Des Chemins de Fer Français
SPANC - Service Public d’Assainissement Non Collectif
TPS - Toute Petite Section (School 2-3 ans)
Resurrecting this topic somewhat with a question that has been on my mind (why, I have no idea, it just popped up one day).
The French love their acronyms as far as I can tell but do they generally try to make pronounceable words from acronyms, or do they sound out each letter?
Best phonetic one for me is PQ
Both 
A few more off the top of my head.
ADMR - Aide a Domicile en Milieu Rural
DMP - Dossier Medical Personnel
EELV - Europe Écologique - Les Verts
LREM - Les Républicains En Marche
NUPES - La Nouvelle Union Populaire Écologique et Sociale
PACS - Pacte Civil de Solidarité
PS - Parti Socialiste
RN - Rassemblement National
Both for an individual acronym or are some “pronounced” and some spelled out?
My personal favourite…
CONSUEL - Comité national pour la sécurité des usagers de l’électricité.
I think people should join my Campaign for the Repudiation of Acronymic Proliferation.
OTAN (ie pronounced, I guess just as we would for NATO)
SAUR - Société d’aménagement urbain et rural
PAF - Police aux frontières
The splendidly named SPANC - SERVICE PUBLIC ASSAINISSEMENT NON COLLECTIF
For the sporting minded:
FFF - Federation Francaise de Football
FFR - Federation Francaise de Rugby
FFT - Federation Francaise de Tennis
etc, etc, etc
UNAF - Union National Arbitres de Football (each department also has a branch, to find it just add the department number, e.g. UNAF24, UNAF47 etc).
An acronym is a word from the initial letters of several words and is spoken as a word.
A group of letters that are spelled/spoken individually is an abbreviation or initialism.
Well, I learned a new word - initialism but otherwise that wasn’t a super helpful post to be frank, because it still does not tell me which are pronounced as words and which as their separate letters.
I’m also not exactly convinced that abbreviations are sounded as separate letters, unless your neighbours invite you round for an A. P. É. R. O and not an apéro.
If you can say it as a word then sometimes we do eg ENA, SMIC, ZEP, but sometimes not eg PLU, DUP, and we can also sometimes use abbreviations eg Assmat for assistante maternelle.
I’m getting the feeling that you just have to know what is right in each case.
Oh goodness I don’t think there’s a rule, alas
And sometimes you don’t use them much at all….amongst anglophones seems the most common would be to refer to CPAM (or the website, Ameli). All my French friends refer to the Caisse.
This made the 7 year old inside me chuckle a little. 
That’s OK, knowing there’s no rule helps, kind of.
I suspect there are also corner cases where it genuinely is “both” - such as “HVAC” which, in the context of air conditioning is generally pronounced “aitch-vac” in English but spelled out as “H. V. A. C” when it means “High Voltage Alternating Current”.