Fourteen months before they host the World Cup, France reached the pinnacle of the rankings for the first time on the back of successive wins on their tour of Japan.
Les Bleus returned home after Saturday's 20-15 victory over the Brave Blossoms in Tokyo, however, so their stay at the top will be brief as the other top teams all play in series deciders next weekend.
World champions South Africa will be confident of beating Wales in the third test in Cape Town to seal their series after a weakened side lost 13-12 at Free State Stadium on Saturday.
The maiden win for the Welsh over the Springboks in South Africa followed Ireland's 23-12 breakthrough victory over the All Blacks in New Zealand.
The Irish moved up to second in the rankings and will go one better if they can overcome the three-times world champions again in Wellington next Saturday to clinch the series.
Southern hemisphere teams have won eight of the nine World Cups and dominated the top spot in the world rankings for most of the 19 years since they were introduced in 2003.
The All Blacks topped the rankings for the best part of a decade from late 2009 but are now down in fourth behind France, Ireland and South Africa.
New Zealand coach Ian Foster said the top teams in the world were closer than at any time he could remember.
"It was a northern hemisphere weekend so while there's a bit of doom and gloom in our camp, it's actually great for world rugby and it sets up next weekend really well," he told reporters on Sunday.
"It's kind of what everyone wanted, except we didn't want it. There's some strong teams out there. We hate losing and it hurts like hell. We still want to be number one."
Since Fosters has taken charge the All Blacks win rate has fallen below 70 percent.
England leapfrogged Australia into fifth place on the back of their 25-17 victory over the Wallabies in Brisbane at the weekend, which also tied up their series ahead of the third test in Sydney this week.
Scotland did the same to Argentina after their win over the Pumas in Salta to level up that series at 1-1, moving into seventh place ahead of Wales with Argentina dropping to ninth.