The page contents are dynamically loaded using javascript. You have to use something like selenium in order to scrape pages that are dynamically loaded. Here is the full code to do it:

import requests
from bs4 import BeautifulSoup
from selenium import webdriver
import time
URL = 'https://www.amazon.de/Sony-Vollformat-Digitalkamera-Megapixel-SEL-2870/dp/B00FWUDEEC/ref=sr_1_4?__mk_de_DE=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=sony+a7&qid=1604245969&quartzVehicle=5-672&replacementKeywords=sony&sr=8-4'

driver = webdriver.Chrome()
driver.get(URL)

time.sleep(4)

soup = BeautifulSoup(driver.page_source,'html5lib')

price = soup.find('span', class_ = 'a-size-medium a-color-price priceBlockBuyingPriceString').text

print(price)

driver.close()

Output:

962,16 €