You will need to be on the webpage where the data is stored, not the webpage with the links to the data. Depending on what format the data is in you will need to change the (sep='\t') to fit your needs,
ex. a csv would be (sep=',')
You will then need to fine tune the formatting.
library(RCurl)
urlcontent<-
getURL('https://www.govdata.de/web/guest/daten/-/details/1c669080-c804-11e4-
8731-1681e6b88ec1bkg')
DATA<- read.table(textConnection(urlcontent), header=T, sep = '\t')
Note the read.table function may only work with a tsv type page, you will need to fine tune the reading of the page based on the formatting.
EDIT:
Using the link address for the URL I was able to successfully grab the URL, the problem though is an access error, I do not have access to download the data. This may be another error in the code, or an actual credential problem on the website side.
library(RCurl)
urlcontent<-
getURL('https://www.govdata.de/ckan/api/rest/dataset/1c669080-c804-11e4-
8731-1681e6b88ec1bkg')
DATA<- read.table(textConnection(urlcontent), header=T, sep = '\t')
Error:You don't have permission to access this server