The CV is the core document of your application. Sometimes it will be the only document that the HR officer reads.
In case of applying for an internship one page of CV should be enough. Not more than two pages! Focus on the facts and skills relevant for the posts offered.
Avoid of gaps in your CV. HR officers will always find that suspicious. At best, they will ask in an interview afterwards; at worst, they will lay a fragmented CV just to the side.
Today, a CV has always to be written in table form. Beware of older guides! Less than 15 years ago it was common to write fully formulated CVs in Germany.
A CV should always include:
Headline: name of the candidate and/or the word "CV"
Photo (see below)
Personal data (name, address, telephone, email address, birth date and place of birth)
Education (schools starting with secondary school, universities, other trainings)
Work experience (former internships and jobs)
Skills (computer skills, languages)
Hobbies / Engagement
A list of own publications (if applicable)
Awards (if applicable)
Place, date, signature
Even though it is controversial discussed (and not even completely legal in Germany since 14/08/2006!), most HR officers in Germany still expect an informative application photo. If they expect one, send them one. But never send a bad-quality, or too private snapshot. Experts agree that the success of an application in Germany is so dependent on the quality of the photo as nowhere else. Ask a professional photographer to take a picture that is both formal and individual. The web is full of bad and good practice examples:
Hold you back with private information. Mention hobbies only, if they are relevant for assessing your personality or for the targeted placement. To name “shopping” or “partying” as hobbies is a knock-out criterion (unless you apply at a respective company).