Via the official site, Rammstein has confirmed that they will be performing at several music festivals in 2013.
The dates so far are:
June 01, 2013 NL- Nijmegen, Goffertpark, Fortarock XL
June 04, 2013 PL- Warsaw, Impact
June 08, 2013 RU- Samara, Rock on Volga /Rock Nad Volgoi
June 13, 2013 CH- Interlaken, Greenfield Festival
June 14, 2013 A- Nickelsdorf, Nova Rock
June 16, 2013 GB- Donington Park, Download Festival
June 21-23, 2013 D- Scheeßel, Hurricane
June 21-23, 2013 D- Neuhausen ob Eck, Southside
July 06, 2013 B- Werchter, Rock Werchter
July 26, 2013 BG- Sofia, Sofia Rocks
July 28, 2013 RO- Bucharest, Romexpo, Rock over Bucharest
August 01, 2013 D- Wacken, Wacken Open Air
Source: Rammstein Official Site and many fans via contact form
UPDATE (3/10/2012): Rammstein has been announced has headliners for Bravalla Festival (Norrköping, Sweden), to occur on June 27, 2013.