* World reformed group says must save by moving from Geneva
* Most donations, fees made in euros and dollars (Updates with background, details)
By Tom Heneghan, Religion Editor
PARIS, Nov 5 (Reuters) - The Swiss city of Geneva has a long history of affording refuge to religious dissenters, most notably the 16th-century reformer John Calvin, but the strong Swiss franc currency has made it hard on his followers.
The exchange rate of the Swiss franc to other currencies has forced the World Communion of Reformed Churches (WCRC) to move its global headquarters, which has a staff of seven, to Germany from the city known as "the Protestant Rome" when Calvin ruled it as a strict theocracy.
A WCRC statement on Monday said the group, representing about 80 million Christians in Reformed, Presbyterian and other churches, would move to Hanover by December 2013. Johannesburg and the Dutch city of Utrecht had also been considered.
"Most WCRC membership fees and donations are made in euros or American dollars that have dropped in value in the past several years against the strong Swiss franc," it said.
The move would bring savings of about 200,000 Swiss francs($212,000) a year in its 1.4 million franc annual budget, it added. Over the past five years, the dollar has lost around 21 percent of its value against the Swiss currency and the euro has lost about 27 percent.
Born in northern France, Calvin was the virtual ruler of Geneva from 1541 until his death in 1564. A tireless preacher, he enforced a strict public morality that prohibited public amusements. Heretics were tortured and some burned at the stake.
The city became a centre of the Reformation and welcomed Protestants who fled from Catholic rulers around Europe. After his death, his ideas spread to France, Germany, England and Scotland, and later with the Puritans to the American colonies.
Geneva commemorated him in 1909 with its Reformation Wall at the university he founded. The city also hosts an International Museum of the Reformation next to its cathedral.
The Reformed church movement has had offices in Geneva since 1948, when the World Council of Churches representing 349 Protestant, Orthodox and Anglican churches opened there.
Addressing a synod of the Evangelical Church in Germany (EKD) on Monday, Chancellor Angela Merkel said the WCRC decision "highlights the positive church-state relations in our country, which is noticed and recognised internationally".
The EKD, Germany's main Protestant church association, is based in Hanover, as are several smaller German church groups.
With about 2.2 billion adherents, Christianity is the world's largest faith. The Roman Catholic Church accounts for 1.2 billion of that total, followed by the Orthodox with over 250 million members and Baptists with around 90 million.
The Reformed, Anglican, Lutheran and Methodist churches each have about 80 million members around the world, many of them in developing countries. (Reporting By Tom Heneghan; Editing by Michael Roddy)