France stood by us, now stand by her
Three-hour-long queues of people waiting to donate blood. Barely 12 hours after their marvellous world city had been turned into a bloody battlefield, people in Paris were trying to cope with deep trauma, intense shock and a sense of powerlessness.
The spontaneous response of ordinary people, wanting to do something positive and helpful by giving blood, speaks to the indomitable nature of humanity and the innate human goodness.
Paris has long been known as 'La Ville Lumière' - 'The City of Light'. For over a thousand years it has been a centre of learning and also celebrated as one of the first cities to adopt street lighting.
It has welcomed people from every country and every culture. People from at least 15 countries died in those three horror attacks on Friday night which struck at a major football match, a music concert and a large outdoor café. An Irishman was among those badly hurt.
So, France is not alone in any of this. The frightening sense of vulnerability which flows from these random and marauding attacks is shared across the globe. People who live in, or regularly visit places such as London, Rome or Brussels, will know that sense of vulnerability.
Irish people will not be so presumptuous as to think our relative smallness, or relatively peripheral location, will necessarily spare us. We are also keenly conscious of Ireland's deep and continuing links with France generally, and Paris in particular.
Ireland's direct links to Paris go back one thousand years to the monks and scholars. These links have been renewed in every generation. To this very day the Irish language is heard in the streets and cafés of Paris through the hundreds of people who comprise 'An Ghaeltacht Sur Seine'.
France has given us the egalitarian model of a republic. The Irish national flag is directly modelled on the French tricolour.
The reflexive response of the majority of Irish people has been a strong expression of sympathy and support for France and the French in this, their darkest hour since 1945.
Saturday and yesterday were days of eerie quiet in Paris and across France. Today begins three days of national mourning. But there are also clear signs that the fight-back is beginning.
The light in the 'City of Light' will not be extinguished.
Realism is reinforced by the presence of legions of armed soldiers and police on the streets of Paris and the other cities. Investigations into security and intelligence failings will be long and rigorous.
The inevitable tightening of security at all levels will impose a big burden on every citizen. It will be extremely difficult to combat this often unseen enemy whose objectives are at best poorly understood.
Maintaining those French-inspired objectives of 'liberté, égalité, fraternité', while framing an adequate security response, will be a huge challenge. So too will be guarding against these atrocities feeding racism, adding to the stock of extremist politicians, and/or stymieing a generous response to refugees who continue flooding into Europe.
There have been early and ominous signs that extremists on the far right may attract some additional support in the wake of Paris attacks. But all mainstream politicians must stand firm and show leadership on this for everyone's sake, if the Isis murder agenda is to be stopped.
Ireland will face its share of all of these challenges in the coming months. But for now our job is much simpler and more urgent: we must show solidarity in order to sustain the light of hope in Paris.