Your message is wrong on so many levels I don't really know how to start.
First, average life expectancy is absolutely not an interesting measure. You should at least look at the average age up to which people are alive and in good health. And this is much lower. Also, life expectancy is very different depending on your social class. Construction workers die much younger than software engineers. And this is even more true regarding life expectancy in good health. By increasing the age at which one can retire, what you actually do is to make the poorer contribute to retirement money they won't be able to benefit of because they'll be dead before or soon after while the rich will enjoy their retirement since they live longer in good health.
Concerning the whole there is more old people thing: yes, there is, but at the same time workers have never been as productive as they're now. And France as never been as rich as it is now. There is no technical problem here, just a political choice. The Cor (Conseil d'orientation des retraites, which is the official institution that studies retirement in France with projections into the future etc) says our retirement system is currently stable with no real risk to its equilibrium (actually there is one scenario over four in which it may temporarily have a deficit in a few years but that resorbs itself over a few years as well — and you have to know that a few years back they made projections and were quite pessimistic for the situation today, but the reality is that nowadays our retirement system is afloat and well, with multiple billions in positive this year for example). Also, there are solutions if we need more contribution to retirement fund: one of which is to increase wages, another one of which is to pay women the same as men (in France the gap is still between 15% and 20%), another one is to tax the richest more, or simply to politically accept to keep the portion of GDP we spend on the elderly the same rather than wanting to keep the absolute amount the same or lower (which is what Macron wants).
Finally, retirement pension is not "giving people money for free". Retired people are not "just consumers", they contribute a lot to society, even if from a capitalist point of view it is not directly visible: more than a third of the volunteering in (quite sadly, indispensable) non-profit is done by young retirees who can still do it, almost half of baby-sitting is done by grand-parents who can do it because they're retired, etc.
What kills the livelyhoods of younger generation is small wages, no political control over rent prices, a partly artificial inflation which main effect is to make everyone pay more at the supermarket to enrich shareholders who bet on the inflation even more, and soon, if this law passes, it will be the burden of having to take care of their parents who could not work til the increased retirement minimum age for health reasons and will therefore have way too small pensions to be independent.
