The 20th century was hard on most of Europe. It was hard on organized religion there, too.

This isn’t something I just now noticed. Though it struck me anew on Sunday as I sat inside the grand — but nearly empty — American Cathedral in Paris.

This is an impressive place, located on Avenue George V, a tony neighborhood near the Champs Elysees — and only a few feet from the posh George V Hotel.

Tall interior columns support a roof at least 50 feet high, and shelter at least 30 rows of pews. I would guess the place seats 250, no problem. Probably 300. A big pipe organ. Lots of stained glass. A steeple reaching high into the Parisian sky.

Presumably, members of the American community built a church this grand and this big because in another time Yanks in Paris (Protestants, anyway; it’s an Episcopal cathedral) were keen to get together for church services with bit of a “home” feel to them.

They consecrated the place in 1886, and it still looks impressive, if a little threadbare, here or there. An interesting collection of flags, hanging over the nave, seem a little moth-eaten.

So few of us were there for the “Sundays at Six” (p.m.) service that the minister, one Elizabeth Hendrick, had us all come up to the altar area and sit in the choir pews. That worked out fine because 25 people can sit up there, no problem.

The service was very nicely done. The entire order of worship was in the bulletin, and could be followed in English or in French. The minister spoke English about 95 percent of the time, but if the 2-3 French people in the church wanted to participate in French, they could.

The homily was based on a reading from Isaiah and pertained to exiles, which is always near to the heart of expats. Reverend Hendrick has a soothing and compelling voice, and she delivered the sermon extemporaneously. That is, it was thoroughly planned and thought out, but she never looked at notes — or even had any to fall back on.

I should add there is nothing quite like being in church far from home to make a person a little verklempt. Much of the liturgy, and certainly the organization of the service, would be familiar to any “mainline” Protestant.

Meanwhile, about 500 yards from where we were sitting, tens of thousands of people were marching up and down the Champs, doing nothing in particular. Certainly, they were not in church.

Anyone who has spent time in Europe knows that very few Europeans are even occasional churchgoers.

I believe they were, before World War I, but I think that the 20th century was so horrible (and that war in particular), and so many governments cloaked themselves in religion, that churches were tainted by the prodigious violence. A whole “where is God in the midst of this?” sense swept the continent, followed by avidly anti-Christian political systems like communism and fascism.

It is eye-opening to come to Europe from the UAE, where Islam is such an important and omnipresent part of life.

When you’re talking about secular nations … well, you can hardly get more secular than France — except when it comes to wanting days off for religious holidays.

The French are remarkably pious, as long as they are being paid not to work. On, say, Assumption, All Saints Day, Good Friday, Easter Monday, etc. They wouldn’t think of working those days.

But when it comes to attending a church, only a tiny fraction of people do so, and most of them seem to be immigrants.  The average Frenchman, like the average German, Swede, Spaniard, Swiss, Dane, Belgian, Hungarian, Bulgarian, Serb … goes to church only for weddings and funerals.