well, the fallout wikis say that while the US and China fought their war for alaska that escalated in the nuclear catastrophy the EC (European Commonwealth) collapsed because Oil/Gas ran short. the european states then massacred each other and fought wars for centuries. every state was fighting for its survivor, until every state fired its nuclear weapons in 2077 (the great war, ya know).

the EC had a united army before and fought against the middle eastern states for resources before they turned against each other.

there are many weapons of the fallout universe that were produced in the states of the EC. only the United Kingdom is confirmed as a member of the EC, but its very likely that germany, italy, france and austria were also part of it. the eastern european states belonged to the Soviet union, as in real life.

tas far as i know there is not muchg known about the CCCP and its relations to the EC.

but let's just assume, that the again independent national states of europe took control over the former EC nuclear weapon arsenal and fired the stuff at each other and the neighbouring countries of the CCCP.

also the US are very likely to have bombarded the CCCP themselves.

all in all we can say that the entire northern hemisphere is as wasted as the Fallout America we know so well.

thats the fallout story so far.

so here's my crap

so what happens to europe in my scenario:
after the nuclear winter every tree was pretty dead or mutated into huge carbuncle-like organisms.
the flat regions such as northwestern france, central/northern germany, and so on turn into arid deserts or steppes.
the steppes are populated by huge insects (like in the fallout series, but also with buffalo-sized herbivore beetles and such [censored]) and giant
meat-eating birds (return of terror birds, mutations of running birds).

the returning civilisation concentrates in the hilly piedmont regions such as the alpine, carpatian, pyrenean forelands. the piedmonts are the only landscape not entirely hostage to life.
like in the former US there are various mutated humanoids. the post-apocalyptical civilisation is a mixture of modern and archaic technologies, using the remaining resources and new mutated species as working animals.

There are 3 main regions now:

#1: mountain rainforests: the radioactive clouds got stuck in the mountainous regions, so this are the most contaminated landscapes. only the toughest, most mutagenious species were able to survive there.
the mountains are now covered in all forms of huge mushrooms (tree size, 720 million years ago they covered the dry land) and radiation-resistant trees (gingko; first tree to grow in hiroshima). humans can only survive with gasmasks in these rainforest hostile to life, because some fungi throw out spores that grow in their lungs and break through their chests after a few weeks. sick [censored], i tell ya
but groups of traders enter the mountain forests from time to time to get highly valuable raw materials like wood, edible fungi, ores, meat, etc.
#2: steppe and deserted wasteland: like in the fallout series populated by giant insects, scorpions, reptiles, rodents and wild dogs,
no really big animals. but the steppe also hosts huge herds of all kinds of herbivore animals and medium scaled carnivores hunting them.
in the north lifeless ice wastes are the dominant landscape.
#3: hill land: towns and cities emerge, trade returns, small empires rise and fall, gangs and nomadic tribes sack settlements. gathering caravans and expeditions are sent into the wasteland and the jungle.
relatively big animals populate the radiated, crippled bushforests and grassy hills. such as rhino-sized beetles, carnivorous terror birds, mutated deers and elephant-sized mammals that evolved from wisents.
in relation to the jungle and wasteland it iss safe in the hill lands, but it's still pretty deadly, just like it should be in a post-apocalyptic world

Livestock and living:
similar to the red carawan in northwest america the trading relies on guarded carawans. the beasts of burden vary from region to region, but the most common pack animals are 2-3 metre tall domesticated flightless birds.
brahmin are unknown in Fallout-Europe, because this cow mutation only spread throughout North America.
but besides the giant birds (imagine them like huge slim chicken with only a few feathers left) there are other farm animals.
f.e. mutated deers, goats, boars, large herbivore insects and so on.

Warfare:
mainly small scaled, just a few thousand men. but tribal alliances sometimes raise big hordes and terrorize the free cities.
most cities are independent citystates, warring each other to defend their trade routes or gain new ones.
the most common way of fighting is infantry melee combat with all kinds of weapons. those who can afford it ride on beasts (mostly terror birds).
some more civilized cities have organized armies, fighting in formation and with good supply routes. the countryside relies on wild mostly uncontrolled mobs and levies.
the armour is ofcourse in the typical style of this genre: rusty trash armour, all kinds of masks, helmets, hats, caps; and ofcourse gas masks and the most important thing: Goggles!
many nomadic tribes specialized in a certain mount (like camels, lamas and horses in Real Life) and are therefore moving fast and agile.

almost nobody is able to produce ammunition, because almost all weapon factories and military bases were destroyed during the resource wars or the great war. only some smaller weapon warehouses are still there. but unexceptional plundered.

so guns, firearms have become very rare. only elite units and royal/republican/urban guards are hoarding guns and ammo to be able to defend themselves if the worst case occurs. some raider and tribal chiefs carry rare weapons as symbols of their power.
but there is a wide range of new and old weapons, thanks to human ingenuity.

i'm thinking of repeating-crossbows and stuff. i will eventually draw something...

Climate and Natural Deasters:

the fallout series tells us that there are no seasons now, just an everlasting summer.

BUT from time to time (a couple of years) the clouds of radiotactive dust get too heavy and cover the landscape in a layer of fallout (radioactive, poisonous ash).

people and animals have to deal with it or die. this accelerates evolution too. in addition to the radiation and the Forced Evolutionary Virus.

thats all of my bullshít for now