Search for Newspapers on Microfilm
Most 20th-21st century newspapers in the Yale Library are on microfilm because of the fragile nature of newsprint. This link will allow you to search for microfilm holdings by city, country, time period and other parameters. See Directions to the Microform Reading Room for more on how to access these.

Search Orbis for Newspapers in all Formats
Orbis provides a more comprehensive search for newspapers in all formats and time periods. To look for French newspapers:

1. Go to Orbis Advanced Search 
2. Select Type = Serials and Journals
3. Search for the keywords: newspapers Berlin [or another city, such as Paris or Rome]

Search Orbis for Newspapers in Electronic Format Only
Follow the same directions as above, but also set: Medium = Electronic Resources

Digitized French Newspapers on Gallica
Free online source provided by the Bibliothèque Nationale allows you to search many French newspapers, mostly from the late 19th-early 20th centuries. Even more periodicals are available through the Advanced Search.

Wikisource Zeitschriften: List of Digitized German Serials 
An extensive list of German-language serials with links to digitized versions, covering all periods of history.